Heterocyclic compound and organic light-emitting device including the same

ABSTRACT

A heterocyclic compound and an organic light-emitting device including the heterocyclic compound, the heterocyclic compound being represented by the following Formula 1:
 
A 1 -(A 2 ) n2 ,  &lt;Formula 1&gt;
         wherein, in Formula 1, A 1  is a group represented by one of Formulae 2A and 2B, and A 2  is a group represented by Formula 3,

CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2016-0098448, filed on Aug. 2, 2016, inthe Korean Intellectual Property Office, and entitled: “HeterocyclicCompound and Organic Light-Emitting Device Including the Same,” isincorporated by reference herein in its entirety.

BACKGROUND 1. Field

Embodiments relate to a heterocyclic compound and an organiclight-emitting device including the same.

2. Description of the Related Art

Organic light-emitting devices are self-emission devices; have wideviewing angles, high contrast ratios, short response times, andexcellent luminance, driving voltage, and response speedcharacteristics; and produce full-color images.

An example of such organic light-emitting devices may include a firstelectrode disposed on a substrate, and a hole transport region, anemission layer, an electron transport region, and a second electrode,which are sequentially disposed on the first electrode. Holes providedfrom the first electrode may move toward the emission layer through thehole transport region, and electrons provided from the second electrodemay move toward the emission layer through the electron transportregion. Carriers, such as holes and electrons, recombine in the emissionlayer to produce excitons. These excitons transition from an excitedstate to a ground state, thereby generating light.

SUMMARY

Embodiments are directed to a heterocyclic compound and an organiclight-emitting device including the same.

The embodiments may be realized by providing a heterocyclic compoundrepresented by Formula 1:A₁-(A₂)_(n2).  <Formula 1>

wherein, in Formula 1,

A₁ may be a group represented by one of Formulae 2A and 2B:

A₂ is a group represented by Formula 3:*-(L)_(a)-(Ar)_(b)  Formula 3

The embodiments may be realized by providing an organic light-emittingdevice, the device including a first electrode; a second electrodefacing the first electrode; and an organic layer between the firstelectrode and the second electrode, the organic layer including anemission layer, wherein the organic layer includes the heterocycliccompound according to an embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will be apparent to those of skill in the art by describing indetail exemplary embodiments with reference to the attached drawings inwhich:

FIG. 1 illustrates a schematic sectional view of an organiclight-emitting device according to an embodiment;

FIG. 2 illustrates a schematic sectional view of an organiclight-emitting device according to an embodiment;

FIG. 3 illustrates a schematic sectional view of an organiclight-emitting device according to an embodiment; and

FIG. 4 illustrates a schematic sectional view of an organiclight-emitting device according to an embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, the presentembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein. Accordingly, theembodiments of the present disclosure are merely described below, byreferring to the figures, to explain aspects of the present description.As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. Expressions such as “atleast one of,” when preceding a list of elements, modify the entire listof elements and do not modify the individual elements of the list. Theterm “or” is not an exclusive term, e.g., A or B means: A, B, or A andB.

A heterocyclic compound according to an embodiment may be represented byFormula 1 below.A₁-(A₂)_(n2).  <Formula 1>

In Formula 1, A₁ may be a group represented by one of Formulae 2A and2B, and A₂ may be a group represented by Formula 3.

n2, X₁ to X₁₀, L, a, Ar, and b in Formulae 1 to 3 are described below.

n2 Formula 1 may be an integer from 1 to 7. In one embodiment, n2 may bean integer from 1 to 3. For example, n2 may be 1 or 2. When n2 is two ormore, groups represented by Formula 3 may be identical to or differentfrom each other.

In Formulae 2A and 2B, X₁ may be N or C(R₁), X₂ may be N or C(R₂), X₃may be N or C(R₃), X₄ may be N or C(R₄), X₅ may be N or C(R₅), X₆ may beN or C(R₆), X₇ may be N or C(R₇), X₈ may be N or C(R₈), X₉ may be N orC(R₉), and X₁₀ may be N or C(R₁₀).

In one embodiment, A₁ may be a group represented by one of Formulae 2Aand 2B, wherein, in Formula 2A, X₁ may be N, X₂ may be C(R₂), X₃ may beC(R₃), X₄ may be C(R₄), X₅ may be C(R₅), X₆ may be C(R₆), X₇ may beC(R₇), X₈ may be C(R₈), X₉ may be C(R₉), and X₁₀ may be C(R₁₀), and atleast one from R₂ to R₁₀ may be a binding site to A₂ in Formula 1; and,in Formula 2B, X₁ may be N, X₂ may be C(R₂), X₃ may be C(R₃), X₄ may beC(R₄), X₆ may be C(R₆), X₇ may be C(R₇), X₈ may be C(R₈), and X₉ may beC(R₉). At least one selected from R₂ to R₄ and R₆ to R₉ may be a bindingsite to A₂ in Formula 1.

In one embodiment, A₁ may be a group represented by one of Formulae 2Aand 2B, wherein, in Formula 2A, X₂ may be N, X₁ may be C(R₁), X₃ may beC(R₃), X₄ may be C(R₄), X₅ may be C(R₅), X₆ may be C(R₆), X₇ may beC(R₇), X₈ may be C(R₈), X₉ may be C(R₉), and X₁₀ may be C(R₁₀), and atleast one selected from R₁ and R₃ to R₁₀ may be a binding site to A₂ inFormula 1; and, in Formula 2B, X₂ may be N, X₁ may be C(R₁), X₃ may beC(R₃), X₄ may be C(R₄), X₆ may be C(R₆), X₇ may be C(R₇), X₈ may beC(R₈), and X₉ may be C(R₉), and at least one selected from R₁, R₃, R₄,and R₆ to R₉ may be a binding site to A₂ in Formula 1.

In one embodiment, A₁ may be a group represented by one of Formulae 2Aand 2B, wherein, in Formula 2A, X₃ may be N, X₁ may be C(R₁), X₂ may beC(R₂), X₄ may be C(R₄), X₅ may be C(R₅), X₆ may be C(R₆), X₇ may beC(R₇), X₈ may be C(R₈), X₉ may be C(R₉), and X₁₀ may be C(R₁₀), and atleast one selected from R₁, R₂ and R₄ to R₁₀ may be a binding site to A₂in Formula 1; and, in Formula 2B, X₃ may be N, X₁ may be C(R₁), X₂ maybe C(R₂), X₄ may be C(R₄), X₆ may be C(R₆), X₇ may be C(R₇), X₈ may beC(R₈), and X₉ may be C(R₉), and at least one selected from R₁, R₂, R₄,and R₆ to R₉ may be a binding site to A₂ in Formula 1.

In one embodiment, A₁ may be a group represented by one of Formulae 2Aand 2B, wherein, in Formula 2A, X₁ and X₃ may each be N, X₂ may beC(R₂), X₄ may be C(R₄), X₅ may be C(R₅), X₆ may be C(R₆), X₇ may beC(R₇), X₈ may be C(R₈), X₉ may be C(R₉), and X₁₀ may be C(R₁₀), and atleast one selected from R₂, R₄ and R₅ to R₁₀ is may be a binding site toA₂ in Formula 1; and, in Formula 2B, X₁ and X₃ may each be N, X₂ may beC(R₂), X₄ may be C(R₄), X₆ may be C(R₆), X₇ may be C(R₇), X₈ may beC(R₈), and X₉ may be C(R₉), and at least one selected from R₂, R₄, andR₆ to R₉ may be a binding site to A₂ in Formula 1.

In one embodiment, A₁ may be a group represented by one of Formulae 2Aand 2B, and, in Formula 2A, X₁ and X₆ may each be N, X₂ may be C(R₂), X₃may be C(R₃), X₄ may be C(R₄), X₅ may be C(R₅), X₇ may be C(R₇), X₈ maybe C(R₈), X₉ may be C(R₉), and X₁₀ may be C(R₁₀), and at least oneselected from R₂ to R₅ and R₇ to R₁₀ may be a binding site to A₂ inFormula 1; and, in Formula 2B, X₁ and X₆ may each be N, X₂ may be C(R₂),X₃ may be C(R₃), X₄ may be C(R₄), X₇ may be C(R₇), X₈ may be C(R₈), andX₉ may be C(R₉), and at least one selected from R₂ to R₄ and R₇ to R₉may be a binding site to A₂ in Formula 1.

In one embodiment, A₁ may be a group represented by Formula 2A, and, inFormula 2A, X₁, X₃, and X₅ may each be N, X₂ may be C(R₂), X₄ may beC(R₄), X₆ may be C(R₆), X₇ may be C(R₇), X₈ may be C(R₈), X₉ may beC(R₉), and X₁₀ may be C(R₁₀), and at least one selected from R₂, R₄ andR₆ to R₁₀ may be a binding site to A₂ in Formula 1.

In Formulae 2A and 2B, at least one from X₁ to X₁₀ may be N. Forexample, two or more from X₁ to X₁₀ in Formula 2A may be N, and two ormore from X₁ to X₄ and X₆ to X₉ in Formula 2B may be N.

R₁ to R₁₀ may each independently be selected from:

a binding site to A₂ in Formula 1, hydrogen, deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a substituted or unsubstitutedC₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group,a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted heterocycloalkyl group,a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substitutedor unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —C(═O)(Q₁), and—P(═O)(Q₁)(Q₂).

In one embodiment, R₁ to R₁₀ may each independently be selected from:

a binding site to A₂ in Formula 1;

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, and ahydrazono group; and—Si(Q₁)(Q₂)(Q₃),

wherein R₁ to R₁₀ may be separate or may optionally be linked to form asubstituted or unsubstituted condensed ring, and

Q₁ to Q₃ may each independently be selected from a C₁-C₁₀ alkyl group, aC₁-C₁₀ alkoxy group, a phenyl group, and a naphthyl group.

R₁ to R₁₀ may optionally form a substituted or unsubstituted condensedring together.

In one embodiment, R₈ and R₉ may form dihydroindole together.

L in Formula 3 may be selected from:

a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substitutedor unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted orunsubstituted C₃-C₁₀ cycloalkenylene group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted orunsubstituted C₆-C₆₀ arylene group, a substituted or unsubstitutedC₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalentnon-aromatic condensed polycyclic group, and a substituted orunsubstituted divalent non-aromatic condensed heteropolycyclic group.

In one embodiment, L in Formula 3 may be selected from:

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anindacenylene group, an acenaphthylene group, a fluorenylene group, aspiro-fluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenalenylene group, a phenanthrenylenegroup, an anthracenylene group, a fluoranthenylene group, atriphenylenylene group, a pyrenylene group, a chrysenylene group, anaphthacenylene group, a picenylene group, a perylenylene group, apentaphenylene group, a hexacenylene group, a pentacenylene group, arubicenylene group, a coronenylene group, an ovalenylene group, apyrrolylene group, a thiophenylene group, a furanylene group, animidazolylene group, a pyrazolylene group, a thiazolylene group, anisothiazolylene group, an oxazolylene group, an isoxazolylene group, apyridinylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, an isoindolylene group, an indolylene group, anindazolylene group, a purinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a carbazolylene group, aphenanthridinylene group, an acridinylene group, a dihydroacridinylenegroup, a phenanthrolinylene group, a phenazinylene group, abenzimidazolylene group, a benzofuranylene group, a benzothiophenylenegroup, an isobenzothiazolylene group, a benzoxazolylene group, anisobenzoxazolylene group, a triazolylene group, a tetrazolylene group,an oxadiazolylene group, a triazinylene group, a dibenzofuranylenegroup, a dibenzothiophenylene group, a benzocarbazolylene group, adibenzocarbazolylene group, a thiadiazolylene group, animidazopyridinylene group, and an imidazopyrimidinylene group; and

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anindacenylene group, an acenaphthylene group, a fluorenylene group, aspiro-fluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenalenylene group, a phenanthrenylenegroup, an anthracenylene group, a fluoranthenylene group, atriphenylenylene group, a pyrenylene group, a chrysenylene group, anaphthacenylene group, a picenylene group, a perylenylene group, apentaphenylene group, a hexacenylene group, a pentacenylene group, arubicenylene group, a coronenylene group, an ovalenylene group, apyrrolylene group, a thiophenylene group, a furanylene group, animidazolylene group, a pyrazolylene group, a thiazolylene group, anisothiazolylene group, an oxazolylene group, an isoxazolylene group, apyridinylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, an isoindolylene group, an indolylene group, anindazolylene group, a purinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a carbazolylene group, aphenanthridinylene group, an acridinylene group, a dihydroacridinylenegroup, a phenanthrolinylene group, a phenazinylene group, abenzimidazolylene group, a benzofuranylene group, a benzothiophenylenegroup, an isobenzothiazolylene group, a benzoxazolylene group, anisobenzoxazolylene group, a triazolylene group, a tetrazolylene group,an oxadiazolylene group, a triazinylene group, a dibenzofuranylenegroup, a dibenzothiophenylene group, a benzocarbazolylene group, adibenzocarbazolylene group, a thiadiazolylene group, animidazopyridinylene group, and an imidazopyrimidinylene group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxylic acidgroup or a salt thereof, a sulfonic acid group or a salt thereof, aphosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptylgroup, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, apentalenyl group, an indenyl group, a naphthyl group, an azulenyl group,a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and—Si(Q₃₁)(Q₃₂)(Q₃₃),

wherein Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, and a naphthylgroup.

In one embodiment, L may be a group represented by one of Formulae 4-1to 4-27:

In Formulae 4-1 to 4-27,

Y₁ may be O, S, C(Z₃)(Z₄), N(Z₅), or Si(Z₆)(Z₇),

Z₁ to Z₇ may each independently be selected from deuterium, —F, —Cl,—Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group,an amidino group, a hydrazine group, a hydrazone group, a carboxylicacid group or a salt thereof, a sulfonic acid group or a salt thereof, aphosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptylgroup, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, apentalenyl group, an indenyl group, a naphthyl group, an azulenyl group,a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a Spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and—Si(Q₃₁)(Q₃₂)(Q₃₃),

wherein Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, and a naphthylgroup,

d2 may be an integer from 0 to 2,

d3 may be an integer from 0 to 3,

d4 may be an integer from 0 to 4,

d5 may be an integer from 0 to 5,

d6 may be an integer from 0 to 6, and

d8 may be an integer from 0 to 8.

For example, L may be a group represented by one of Formulae 4-1, 4-2,and 4-27.

Z₁ and Z₂ in Formulae 4-1, 4-2, and 4-27 may each independently beselected from:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group,an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a thiadiazolyl group, animidazopyridinyl group, an imidazopyrimidinyl group, and—Si(Q₃₁)(Q₃₂)(Q₃₃), wherein Q₃₁ to Q₃₃ may each independently beselected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenylgroup, and a naphthyl group.

a may be an integer from 0 to 3. For example, a may be 0 or 1. When a istwo or more, L(s) may be identical to or different from each other.

Ar in Formula 3 may be selected from:

a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted orunsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstitutedheterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, asubstituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted monovalentnon-aromatic condensed heteropolycyclic group.

In one embodiment, Ar may be selected from:

a group represented by one of Formulae 5-1 to 5-8;

a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group,an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group a dibenzosilolyl group, a thiadiazolylgroup, an imidazopyridinyl group and an imidazopyrimidinyl group; and

a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group,an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group a dibenzosilolyl group, a thiadiazolylgroup, an imidazopyridinyl group, and an imidazopyrimidinyl group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxylic acidgroup or a salt thereof, a sulfonic acid group or a salt thereof, aphosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptylgroup, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, apentalenyl group, an indenyl group, a naphthyl group, an azulenyl group,a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and—Si(Q₃₁)(Q₃₂)(Q₃₃).

In Formulae 5-1 to 5-8,

Y₂₁ may be 0 or S, at least one of Y₂₂ and Y₂₃ may be N,

Z₂₁ to Z₂₄ may each independently be selected from deuterium, —F, —Cl,—Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, aC₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, acycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenylgroup, a biphenyl group, a terphenyl group, a pentalenyl group, anindenyl group, a naphthyl group, an azulenyl group, an indacenyl group,an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, aspiro-benzofluorene-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a perylenyl group, a pentacenyl group,a pyrrolyl group, a thiophenyl group, a furanyl group, a silolyl group,an imidazolyl group, a pyrazolyl group, a thiazolyl group, anisothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anindolyl group, an isoindolyl group, an indazolyl group, a purinyl group,a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, anisoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a benzoquinoxalinyl group, a quinazolinyl group, abenzoquinazolinyl group, a cinnolinyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, abenzosilolyl group, a benzothiazolyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, a carbazolylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, adibenzosilolyl group, a benzocarbazolyl group, a naphthobenzofuranylgroup, a naphthobenzothiophenyl group, a naphthobenzosilolyl group, adibenzocarbazolyl group, a dinaphthofuranyl group, dinaphthothiophenylgroup, a dinaphthosilolyl group, a thiadiazolyl group, animidazopyridinyl group, an imidazopyrimidinyl group, an oxazolopyridinylgroup, a thiazolopyridinyl group, a benzonaphthyridinyl group, anazafluorenyl group, an azaspiro-bifluorenyl group, an azacarbazolylgroup, an azadibenzofuranyl group, an azadibenzothiophenyl group, anazadibenzosilolyl group, an indenopyrrolyl group, an indolopyrrolylgroup, an indenocarbazolyl group, an indolocarbazolyl group, abenzoacridinyl group, a benzophenanthrenyl group, a dibenzophenanthrenylgroup, a benzophenanthridinyl group, a dibenzophenanthridinyl group, anindenophenanthrenyl group, an indolophenanthrenyl group, abenzofuranophenanthrenyl group, a benzothiophenanthrenyl group, abenzosilolphenanthrenyl group, an indenophenanthridinyl group, anindolophenanthridinyl group, a benzofuranophenanthridinyl group, abenzothiophenanthridinyl group, a benzosilolphenanthridinyl group, adinaphthopyrrolyl group, a benzoanthracenyl group, and—Si(Q₃₁)(Q₃₂)(Q₃₃),

wherein Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, and a naphthylgroup,

f2 may be an integer from 0 to 2,

f3 may be an integer from 0 to 3,

f4 may be an integer from 0 to 4, and

f5 may be an integer from 0 to 5:

In one embodiment, Ar may be selected from

a group represented by one of Formulae 5-1 to 5-8; and

a group represented by one of Formulae 6-1 to 6-55:

Y₂₁, Y₂₂, Y₂₃, and Z₂₁ to Z₂₄ in Formulae 5-1 to 5-8 may be the same asdescribed above, and

in Formulae 6-1 to 6-55,

Y₃₁ may be O, S, C(Z₃₅)(Z₃₆), N(Z₃₇), or Si(Z₃₈)(Z₃₉),

Z₃₁ to Z₃₉ may each independently be selected from deuterium, —F, —Cl,—Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, aC₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, acycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenylgroup, a biphenyl group, a terphenyl group, a pentalenyl group, anindenyl group, a naphthyl group, an azulenyl group, an indacenyl group,an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, aspiro-benzofluorene-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a perylenyl group, a pentacenyl group,a pyrrolyl group, a thiophenyl group, a furanyl group, a silolyl group,an imidazolyl group, a pyrazolyl group, a thiazolyl group, anisothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anindolyl group, an isoindolyl group, an indazolyl group, a purinyl group,a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, anisoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a benzoquinoxalinyl group, a quinazolinyl group, abenzoquinazolinyl group, a cinnolinyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, abenzosilolyl group, a benzothiazolyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, a carbazolylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, adibenzosilolyl group, a benzocarbazolyl group, a naphthobenzofuranylgroup, a naphthobenzothiophenyl group, a naphthobenzosilolyl group, adibenzocarbazolyl group, a dinaphthofuranyl group, dinaphthothiophenylgroup, a dinaphthosilolyl group, a thiadiazolyl group, animidazopyridinyl group, an imidazopyrimidinyl group, an oxazolopyridinylgroup, a thiazolopyridinyl group, a benzonaphthyridinyl group, anazafluorenyl group, an azaspiro-bifluorenyl group, an azacarbazolylgroup, an azadibenzofuranyl group, an azadibenzothiophenyl group, anazadibenzosilolyl group, an indenopyrrolyl group, an indolopyrrolylgroup, an indenocarbazolyl group, an indolocarbazolyl group,benzoacridinyl group, a benzophenanthrenyl group, a dibenzophenanthrenylgroup, a benzophenanthridinyl group, a dibenzophenanthridinyl group, anindenophenanthrenyl group, an indolophenanthrenyl group, abenzofuranophenanthrenyl group, a benzothiophenanthrenyl group, abenzosilolphenanthrenyl group, an indenophenanthridinyl group, anindolophenanthridinyl group, benzofuranophenanthridinyl group, abenzothiophenanthridinyl group, a benzosilolphenanthridinyl group, adinaphthopyrrolyl group, a benzoanthracenyl group, and—Si(Q₃₁)(Q₃₂)(Q₃₃), wherein Q₃₁ to Q₃₃ may each independently beselected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenylgroup, and a naphthyl group,

e2 may be an integer from 0 to 2,

e3 may be an integer from 0 to 3,

e4 may be an integer from 0 to 4,

e5 may be an integer from 0 to 5, and

e6 may be an integer from 0 to 6.

For example, Ar may be a group represented by one of Formulae 5-1 to5-8, Formulae 6-1 to 6-3, 6-13 to 6-16, 6-37 to 6-39, 6-47, 6-48, and6-50 to 6-55.

b may be an integer from 1 to 4. In one embodiment, b may be an integerfrom 1 to 3. For example, b may be an integer of 1 or 2. When b is twoor more, Ar(s) may be identical to or different from each other.

In an implementation, the heterocyclic compound represented by Formula 1may be one of Compounds 1 to 102

The heterocyclic compound represented by Formula 1 includes a sulfoxidestructure having a strong electron-accepting capability. Accordingly, anelectron-accepting sulfoxide substituent may function as a strongelectron acceptor, and may be paired with an electron donor that is tobe combined with sulfoxide to form a donor-acceptor type compound.Accordingly, strong emission characteristics based on intramolecularcharge transfer-type transition may be obtained.

Also, at least one N-containing 6-membered aromatic ring may be combinedwith the sulfoxide structure to easily adjust an energy level andmolecular polarity to be appropriate for an organic light-emittingdevice having a specific structure, leading to an improvement incharacteristics of the organic light-emitting device.

A molecular polarity difference may affect an molecular energy level andan intermolecular interaction, resulting in a change in hole mobilityand electron mobility of an organic light-emitting device. As a result,the controlling of molecular polarity may be closely related tocharacteristics of the organic light-emitting device.

A heterocyclic compound having a donor-acceptor structure based on thesulfoxide structure according to the present disclosure may be useful todevelop a dopant that is to be optimally combined with a host. Also,according to a substituent or where the substituent is linked, theheterocyclic compound having the sulfoxide substituent may be used as,in addition to the dopant, a host, and a material for forming anelectron transport layer.

A synthesis method for the heterocyclic compound represented by Formula1 would be apparent by referring to the following examples.

At least one heterocyclic compound represented by Formula 1 may beincluded between a pair of electrodes of an organic light-emittingdevice. For example, the heterocyclic compound may be included in anelectron transport region or an emission layer. In one or moreembodiments, the heterocyclic compound of Formula 1 may be used as amaterial for a capping layer located outside a pair of electrodes of anorganic light-emitting device.

According to another aspect of embodiments, an organic light-emittingdevice may include, e.g., a first electrode, a second electrode, and anorganic layer between the first electrode and the second electrode, theorganic layer including an emission layer. The organic layer may includeat least one heterocyclic compound represented by Formula 1 describedabove.

The expression “(an organic layer) includes at least one heterocycliccompound” used herein may include a case in which “(an organic layer)includes identical heterocyclic compounds represented by Formula 1” anda case in which “(an organic layer) includes two or more differentheterocyclic compounds represented by Formula 1.”

For example, the organic layer may include, as the heterocycliccompound, only Compound 1. In this regard, Compound 1 may exist in anemission layer of the organic light-emitting device. In one or moreembodiments, the organic layer may include, as the heterocycliccompound, Compound 1 and a Compound 2. In this regard, Compound 1 and aCompound 2 may exist in an identical layer (for example, Compound 1 anda Compound 2 may all exist in an emission layer), or different layers(for example, Compound 1 may exist in an emission layer and a Compound 2may exist in an electron transport layer).

The organic layer may include i) a hole transport region that isdisposed between the first electrode (anode) and the emission layer andincludes at least one of a hole injection layer, a hole transport layer,a buffer layer, and an electron blocking layer, and ii) an electrontransport region that is disposed between the emission layer and thesecond electrode (cathode) and includes at least one selected from ahole blocking layer, an electron transport layer, and an electroninjection layer. The electron transport region or the emission layer mayinclude at least one heterocyclic compound represented by Formula 1. Inone embodiment, the organic light-emitting device may include anemission layer, which includes the heterocyclic compound represented byFormula 1. The emission layer may include a host and a dopant, and oneof the host or the dopant may include at least one heterocyclic compoundrepresented by Formula 1. The heterocyclic compound represented byFormula 1 included in the emission layer may act as a host, and, in thiscase, the emission layer may further include a dopant to be describedbelow. In one embodiment, the heterocyclic compound represented byFormula 1 included in the emission layer may act as a dopant, and, inthis case, the emission layer may further include a host to be describedlater.

The organic light-emitting device may further include at least oneselected from a first capping layer disposed in a pathway along whichlight generated in an emission layer proceeds toward outside through thefirst electrode and a second capping layer disposed in a pathway alongwhich light generated in an emission layer proceeds toward outsidethrough the second electrode, and the at least one selected from thefirst capping layer and the second capping layer may include at leastone of the heterocyclic compounds.

For example, the organic light-emitting device may have i) a stackstructure including a first electrode, an organic layer, a secondelectrode, and a second capping layer which are sequentially stacked inthis stated order, ii) a stack structure including a first cappinglayer, a first electrode, an organic layer, and a second electrode whichare sequentially stacked in this stated order, or iii) a stack structureincluding a first capping layer, a first electrode, an organic layer, asecond electrode, and a second capping layer which are sequentiallystacked in this stated order, and at least one selected from the firstcapping layer and the second capping layer may include the heterocycliccompound.

The term “organic layer” used herein refers to a single layer and/or aplurality of layers disposed between the first electrode and the secondelectrode of the organic light-emitting device. A material included inthe “organic layer” is not limited to an organic material.

FIG. 1 illustrates a schematic view of an organic light-emitting device10 according to an embodiment. The organic light-emitting device 10 mayinclude a first electrode 110, an organic layer 150, and a secondelectrode 190.

Hereinafter, the structure of the organic light-emitting device 10according to an embodiment and a method of manufacturing the organiclight-emitting device 10 will be described in connection with FIG. 1.

In an implementation, a substrate may be additionally disposed under thefirst electrode 110 or above the second electrode 190. The substrate maybe a glass substrate or a plastic substrate, each having excellentmechanical strength, thermal stability, transparency, surfacesmoothness, ease of handling, and water-resistance.

The first electrode 110 may be formed by depositing or sputtering amaterial for forming the first electrode 110 on the substrate. When thefirst electrode 110 is an anode, the material for a first electrode maybe selected from materials with a high work function to facilitate holeinjection.

The first electrode 110 may be a reflective electrode, asemi-transmissive electrode, or a transmissive electrode. When the firstelectrode 110 is a transmissible electrode, a material for forming afirst electrode may be selected from indium tin oxide (ITO), indium zincoxide (IZO), tin oxide (SnO₂), zinc oxide (ZnO), and any combinationsthereof. In one or more embodiments, when the first electrode 110 is asemi-transmissible electrode or a reflectable electrode, a material forforming a first electrode may be selected from magnesium (Mg), silver(Ag), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca),magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), and any combinationsthereof.

The first electrode 110 may have a single-layered structure, or amulti-layered structure including two or more layers. For example, thefirst electrode 110 may have a three-layered structure of ITO/Ag/ITO.

The organic layer 150 is disposed on the first electrode 110. Theorganic layer 150 may include an emission layer.

The organic layer 150 may further include a hole transport regionbetween the first electrode 110 and the emission layer, and an electrontransport region between the emission layer and the second electrode190.

The hole transport region may have i) a single-layered structureincluding a single layer including a single material, ii) asingle-layered structure including a single layer including a pluralityof different materials, or iii) a multi-layered structure having aplurality of layers including a plurality of different materials.

The hole transport region may include at least one layer selected from ahole injection layer (HIL), a hole transport layer (HTL), an emissionauxiliary layer, and an electron blocking layer (EBL).

For example, the hole transport region may have a single-layeredstructure including a single layer including a plurality of differentmaterials, or a multi-layered structure having a hole injectionlayer/hole transport layer structure, a hole injection layer/holetransport layer/emission auxiliary layer structure, a hole injectionlayer/emission auxiliary layer structure, a hole transportlayer/emission auxiliary layer structure, or a hole injection layer/holetransport layer/electron blocking layer structure, wherein for eachstructure, constituting layers are sequentially stacked from the firstelectrode 110 in this stated order.

The hole transport region may include at least one selected fromm-MTDATA, TDATA, 2-TNATA, NPB(NPD), β-NPB, TPD, Spiro-TPD, Spiro-NPB,methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine(TCTA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA),poly(3,4-ethylenedi oxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS),polyaniline/camphor sulfonic acid (PANI/CSA),polyaniline/poly(4-styrenesulfonate) (PANI/PSS), a compound representedby Formula 201, and a compound represented by Formula 202:

In Formulae 201 and 202,

L₂₀₁ to L₂₀₄ are each independently selected from a substituted orunsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

L₂₀₅ may be selected from *—O—*′, *—S—*′, *—N(Q₂₀₁)-*′, a substituted orunsubstituted C₁-C₂₀ alkylene group, a substituted or unsubstitutedC₂-C₂₀ alkenylene group, a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

xa1 to xa4 may each independently be an integer from 0 to 3,

xa5 may be an integer from 1 to 10,

R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independently be selected from asubstituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted orunsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group.

In one embodiment, in Formula 202, R₂₀₁ and R₂₀₂ may optionally belinked via a single bond, a dimethyl-methylene group, or adiphenyl-methylene group, and R₂₀₃ and R₂₀₄ may optionally be linked viaa single bond, a dimethyl-methylene group, or a diphenyl-methylenegroup.

In one or more embodiments, in Formulae 201 and 202,

L₂₀₁ to L₂₀₅ may each independently be selected from:

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anindacenylene group, an acenaphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenalenylene group, a phenanthrenylenegroup, an anthracenylene group, a fluoranthenylene group, atriphenylenylene group, a pyrenylene group, a chrysenylene group, anaphthacenylene group, a picenylene group, a perylenylene group, apentaphenylene group, a hexacenylene group, a pentacenylene group, arubicenylene group, a coronenylene group, an ovalenylene group, athiophenylene group, a furanylene group, a carbazolylene group, anindolylene group, an isoindolylene group, a benzofuranylene group, abenzothiophenylene group, a dibenzofuranylene group, adibenzothiophenylene group, a benzocarbazolylene group, adibenzocarbazolylene group, dibenzosilolylene group, and a pyridinylenegroup; and

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anindacenylene group, an acenaphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenalenylene group, a phenanthrenylenegroup, an anthracenylene group, a fluoranthenylene group, atriphenylenylene group, a pyrenylene group, a chrysenylene group, anaphthacenylene group, a picenylene group, a perylenylene group, apentaphenylene group, a hexacenylene group, a pentacenylene group, arubicenylene group, a coronenylene group, an ovalenylene group, athiophenylene group, a furanylene group, a carbazolylene group, anindolylene group, an isoindolylene group, a benzofuranylene group, abenzothiophenylene group, a dibenzofuranylene group, adibenzothiophenylene group, a benzocarbazolylene group, adibenzocarbazolylene group, dibenzosilolylene group, and a pyridinylenegroup, each substituted with at least one selected from deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, aC₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, acycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenylgroup, a biphenyl group, a terphenyl group, a phenyl group substitutedwith a C₁-C₁₀ alkyl group, a phenyl group substituted with F, apentalenyl group, an indenyl group, a naphthyl group, an azulenyl group,a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group.

In one or more embodiments, xa1 to xa4 may each independently be 0, 1,or 2.

In one or more embodiments, xa5 may be 1, 2, 3, or 4.

In one or more embodiments, R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independentlybe selected from a phenyl group, a biphenyl group, a terphenyl group, apentalenyl group, an indenyl group, a naphthyl group, an azulenyl group,a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, and apyridinyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group,an indenyl group, a naphthyl group, an azulenyl group, a heptalenylgroup, an indacenyl group, an acenaphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenalenyl group, a phenanthrenyl group, an anthracenyl group,a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, achrysenyl group, a naphthacenyl group, a picenyl group, a perylenylgroup, a pentaphenyl group, a hexacenyl group, a pentacenyl group, arubicenyl group, a coronenyl group, an ovalenyl group, a thiophenylgroup, a furanyl group, a carbazolyl group, an indolyl group, anisoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, and apyridinyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted withF, a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ are the same as described above.

In one or more embodiments, at least one from R₂₀₁ to R₂₀₃ may eachindependently be selected from:

a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group; and

a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenylgroup, a terphenyl group, a phenyl group substituted with a C₁-C₁₀ alkylgroup, a phenyl group substituted with F, a naphthyl group, a fluorenylgroup, a spiro-bifluorenyl group, a carbazolyl group, a dibenzofuranylgroup, and a dibenzothiophenyl group.

In one or more embodiments, i) R₂₀₁ and R₂₀₂ in Formula 202 may belinked via a single bond, and/or ii) R₂₀₃ and R₂₀₄ may be linked via asingle bond.

In one or more embodiments, at least one from R₂₀₁ to R₂₀₄ in Formula202 may be selected from:

a carbazolyl group; and

a carbazolyl group, substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted withF, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, acarbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group.

The compound represented by Formula 201 may be represented by Formula201A:

In one embodiment, the compound represented by Formula 201 may berepresented by Formula 201A(1) below:

In one embodiment, the compound represented by Formula 201 may berepresented by Formula 201A-1 below:

In one embodiment, the compound represented by Formula 202 may berepresented by Formula 202A:

In one embodiment, the compound represented by Formula 202 may berepresented by Formula 202A-1:

In Formulae 201A, 201A(1), 201A-1, 202A, and 202A-1,

L₂₀₁ to L₂₀₃, xa1 to xa3, xa5, and R₂₀₂ to R₂₀₄ are the same asdescribed above,

R₂₁₁ and R₂₁₂ may be the same as described in connection with R₂₀₃.

R₂₁₃ to R₂₁₇ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted withF, a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, and apyridinyl group.

The hole transport region may include at least one compound selectedfrom Compounds HT1 to HT39:

A thickness of the hole transport region may be in a range of about 100Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When thehole transport region includes at least one of a hole injection layerand a hole transport layer, a thickness of the hole injection layer maybe in a range of about 100 Å to about 9,000 Å, for example, about 100 Åto about 1,000 Å, and a thickness of the hole transport layer may be ina range of about 50 Å to about 2,000 Å, for example about 100 Å to about1,500 Å. When the thicknesses of the hole transport region, the holeinjection layer and the hole transport layer are within these ranges,satisfactory hole transporting characteristics may be obtained without asubstantial increase in driving voltage.

The emission auxiliary layer may increase light-emission efficiency bycompensating for an optical resonance distance according to thewavelength of light emitted by an emission layer, and the electronblocking layer may block the flow of electrons from an electrontransport region. The emission auxiliary layer and the electron blockinglayer may include the materials as described above.

The hole transport region may further include, in addition to thesematerials, a charge-generation material for the improvement ofconductive properties. The charge-generation material may behomogeneously or non-homogeneously dispersed in the hole transportregion.

The charge-generation material may be, for example, a p-dopant.

In one embodiment, a lowest unoccupied molecular orbital (LUMO) of thep-dopant may be −3.5 eV or less.

The p-dopant may include at least one selected from a quinonederivative, a metal oxide, and a cyano group-containing compound.

For example, the p-dopant may include at least one selected from:

a quinone derivative, such as tetracyanoquinodimethane (TCNQ) and2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ);

a metal oxide, such as tungsten oxide or molybdenum oxide;

1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN); and

a compound represented by Formula 221 below:

In Formula 221,

R₂₂₁ to R₂₂₃ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, asubstituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted monovalentnon-aromatic condensed heteropolycyclic group, provided that at leastone selected from R₂₂₁ to R₂₂₃ has at least one substituent selectedfrom a cyano group, —F, —Cl, —Br, —I, a C₁-C₂₀ alkyl group substitutedwith —F, a C₁-C₂₀ alkyl group substituted with —Cl, a C₁-C₂₀ alkyl groupsubstituted with —Br, and a C₁-C₂₀ alkyl group substituted with —I.

When the organic light-emitting device 10 is a full color organiclight-emitting device, the emission layer may be patterned into a redemission layer, a green emission layer, or a blue emission layer,according to a sub pixel. In one or more embodiments, the emission layermay have a stacked structure of two or more layers selected from a redemission layer, a green emission layer, and a blue emission layer, inwhich the two or more layers contact each other or are separated fromeach other. In one or more embodiments, the emission layer may includetwo or more materials selected from a red-light emission material, agreen-light emission material, and a blue-light emission material, inwhich the two or more materials are mixed with each other in a singlelayer to emit white light.

The emission layer may include a host and a dopant. The dopant mayinclude at least one selected from a phosphorescent dopant and afluorescent dopant.

An amount of the dopant in the emission layer may be, e.g., in a rangeof about 0.01 to about 15 parts by weight based on 100 parts by weightof the host.

A thickness of the emission layer may be in a range of about 100 Å toabout 1,000 Å, e.g., about 200 Å to about 600 Å. When the thickness ofthe emission layer is within this range, excellent light-emissioncharacteristics may be obtained without a substantial increase indriving voltage.

In one or more embodiments, the host may further include, the condensedcyclic compound represented by Formula 1, a compound represented byFormula 301 below:[Ar₃₀₁]_(xb11)-[(L₃₀₁)_(xb1)-R₃₀₁]_(xb21).  <Formula 301>

In Formula 301,

Ar₃₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group ora substituted or unsubstituted C₁-C₆₀ heterocyclic group,

xb11 may be 1, 2, or 3,

L₃₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group;

xb1 may be an integer selected from 0 to 5,

R₃₀₁ may be selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,a cyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a substituted or unsubstituted C₁-C₆₀ alkyl group, asubstituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted orunsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstitutedC₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂),—B(Q₃₀₁)(Q₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and —P(═O)(Q₃₀₁)(Q₃₀₂), and

xb21 may be an integer selected from 1 to 5,

wherein Q₃₀₁ to Q₃₀₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group.

In one embodiment, Ar₃₀₁ in Formula 301 may be selected from:

a naphthalene group, a fluorene group, a spiro-bifluorene group, abenzofluorene group, a dibenzofluorene group, a phenalene group, aphenanthrene group, an anthracene group, a fluoranthene group, atriphenylene group, a pyrene group, a chrysene group, naphthacene group,a picene group, a perylene group, a pentaphene group, anindenoanthracene group, a dibenzofuran group and a dibenzothiophenegroup; and

a naphthalene group, a fluorene group, a spiro-bifluorene group, abenzofluorene group, a dibenzofluorene group, a phenalene group, aphenanthrene group, an anthracene group, a fluoranthene group, atriphenylene group, a pyrene group, a chrysene group, naphthacene group,a picene group, a perylene group, a pentaphene group, anindenoanthracene group, a dibenzofuran group, and a dibenzothiophenegroup, each substituted with at least one selected from deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, aC₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),—C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group.

When xb11 in Formula 301 is two or more, two or more Ar₃₀₁(s) may belinked via a single bond.

In one or more embodiments, the organometallic compound represented byFormulae 301 may be represented by Formulae 301-1 or 301-2:

In Formulae 301-1 to 301-2,

A₃₀₁ to A₃₀₄ may each independently be selected from a benzene group, anaphthalene group, a phenanthrene group, a fluoranthene group, atriphenylene group, a pyrene group, a chrysene group, a pyridine group,a pyrimidine group, an indene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,an indole group, a carbazole group, a benzocarbazole group, adibenzocarbazole group, a furan group, a benzofuran group, adibenzofuran group, a naphthofuran group, a benzonaphthofuran group, adinaphthofuran group, a thiophene group, a benzothiophene group, adibenzothiophene group, a naphthothiophene group, abenzonaphthothiophene group, and a dinaphthothiophene group,

X₃₀₁ may be O, S, or N-[(L₃₀₄)_(xb4)-R₃₀₄],

R₃₁₁ to R₃₁₄ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),—B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

xb22 and xb23 may each independently be 0, 1, or 2,

L₃₀₁, xb1, R₃₀₁ and Q₃₁ to Q₃₃ may be the same as described above,

L₃₀₂ to L₃₀₄ may each independently be the same as described inconnection with L₃₀₁,

Xb2 to xb4 may each independently be the same as described in connectionwith xb1,

R₃₀₂ to R₃₀₄ may each independently be the same as described inconnection with R₃₀₁.

For example, L₃₀₁ to L_(30z) in Formulae 301, 301-1, and 301-2 may eachindependently be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group,dibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group,dibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, anaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group,an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenylgroup, a hexacenyl group, a pentacenyl group, a thiophenyl group, afuranyl group, a carbazolyl group, an indolyl group, an isoindolylgroup, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranylgroup, a dibenzothiophenyl group, a benzocarbazolyl group, adibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, anoxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, aphenanthridinyl group, an acridinyl group, a phenanthrolinyl group, aphenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, abenzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinylgroup, an azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),—B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ are the same as described above.

In one embodiment, R₃₀₁ to R₃₀₄ in Formulae 301, 301-1, and 301-2 mayeach independently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, aperylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a thiophenyl group, a furanyl group, a carbazolyl group, anindolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ may be the same as described above.

In one or more embodiments, the host may include an alkaline-earth metalcomplex. For example, the host may be selected from a Be complex (forexample, Compound H55), an Mg complex, and a Zn complex.

The host may include, in addition to the heterocyclic compound, at leastone selected from 9,10-di(2-naphthyl)anthracene (ADN),2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN),9,10-di-(2-naphthyl)-2-t-butyl-anthracene (TBADN),4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-di-9-carbazolylbenzene(mCP), 1,3,5-tri(carbazol-9-yl)benzene (TCP), and a Compounds H1 to H55:

The dopant may further include, in addition to the heterocycliccompound, a phosphorescent dopant or a fluorescent dopant which are tobe described below.

The phosphorescent dopant may include an organometallic complexrepresented by Formula 401:

In Formulae 401 and 402,

M may be selected from iridium (Ir), platinum (Pt), palladium (Pd),osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu),terbium (Tb), rhodium (Rh), and thulium (Tm),

L₄₀₁ may be selected from ligands represented by Formula 402, and xc1may be 1, 2, or 3, wherein, when xc1 is two or more, two or more L₄₀₁(s)may be identical to or different from each other,

L₄₀₂ may be an organic ligand, and xc2 may be an integer selected from 0to 4, wherein when xc2 is two or more, two or more L₄₀₂(s) may beidentical to or different from each other,

X₄₀₁ to X₄₀₄ may each independently be nitrogen or carbon,

X₄₀₁ and X₄₀₃ may be linked via a single bond or a double bond, and X₄₀₂and X₄₀₄ may be linked via a single bond or a double bond,

A₄₀₁ and A₄₀₂ may each independently be selected from a C₅-C₆₀carbocyclic group or a C₁-C₆₀ heterocyclic group,

X₄₀₅ may be a single bond, *—O—*′, *—S—*′, *—C(═O)—*′, *—N(Q₄₁₁)-*′,*—C(Q₄₁₁)(Q₄₁₂)-′, *—C(Q₄₁₁)═C(Q₄₁₂)-*′, *—C(Q₄₁₁)=*′, or *—C(Q₄₁₁)=*′,wherein Q₄₁₁ and Q₄₁₂ may be hydrogen, deuterium, a C₁-C₂₀ alkyl group,a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, or a naphthyl group,

X₄₀₆ may be a single bond, O, or S,

R₄₀₁ and R₄₀₂ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, asubstituted or unsubstituted C₁-C₂₀ alkyl group, a substituted orunsubstituted C₁-C₂₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group and a substituted or unsubstituted monovalentnon-aromatic condensed heteropolycyclic group —Si(Q₄₀₁)(Q₄₀₂)(Q₄₀₃),—N(Q₄₀₁)(Q₄₀₂), —B(Q₄₀₁)(Q₄₀₂), —C(═O)(Q₄₀₁), —S(═O)₂(Q₄₀₁), and—P(═O)(Q₄₀₁)(Q₄₀₂), wherein Q₄₀₁ to Q₄₀₃ may each independently beselected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a C₆-C₂₀ arylgroup, and a C₁-C₂₀ heteroaryl group,

xc11 and xc12 may each independently be an integer selected from 0 to10, and

* and *′ in Formula 402 each indicate a binding site to M in Formula401.

In one embodiment, A₄₀₁ and A₄₀₂ in Formula 402 may each independentlybe selected from a benzene group, a naphthalene group, a fluorene group,a spiro-bifluorene group, an indene group, a pyrrole group, a thiophenegroup, a furan group, an imidazole group, a pyrazole group, a thiazolegroup, an isothiazole group, an oxazole group, an isoxazole group, apyridine group, a pyrazine group, a pyrimidine group, a pyridazinegroup, a quinoline group, an isoquinoline group, a benzoquinoline group,a quinoxaline group, a quinazoline group, a carbazole group, abenzimidazole group, a benzofuran group, a benzothiophene group, anisobenzothiophene group, a benzoxazole group, an isobenzoxazole group, atriazole group, a tetrazole group, an oxadiazole group, a triazinegroup, a dibenzofuran group, and a dibenzothiophene group.

In one or more embodiments, in Formula 402, i) X₄₀₁ may be nitrogen, andX₄₀₂ may be carbon, or ii) X₄₀₁ and X₄₀₂ may each be nitrogen at thesame time.

In one or more embodiments, R₄₀₁ and R₄₀₂ in Formula 402 may eachindependently be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a phenyl group, a naphthyl group, a cyclopentyl group,a cyclohexyl group, an adamantanyl group, a norbornanyl group, and anorbornenyl group;

a cyclopentyl group, a cyclohexyl group, an adamantanyl group, anorbornanyl group, a norbornenyl group, a phenyl group, a biphenylgroup, a terphenyl group, a naphthyl group, a fluorenyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group;

a cyclopentyl group, a cyclohexyl group, an adamantanyl group, anorbornanyl group, a norbornenyl group a phenyl group, a biphenyl group,a terphenyl group, a naphthyl group, a fluorenyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, atriazinyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a carbazolyl group, adibenzofuranyl group. and a dibenzothiophenyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, acyclopentyl group, a cyclohexyl group, an adamantanyl group, anorbornanyl group, a norbornenyl group, a phenyl group, a biphenylgroup, a terphenyl group, a naphthyl group, a fluorenyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group; and

—Si(Q₄₀₁)(Q₄₀₂)(Q₄₀₃), —N(Q₄₀₁)(Q₄₀₂), —B(Q₄₀₁)(Q₄₀₂), —C(═O)(Q₄₀₁),—S(═O)₂(Q₄₀₁), and —P(═O)(Q₄₀₁)(Q₄₀₂),

wherein Q₄₀₁ to Q₄₀₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group,and a naphthyl group.

In one or more embodiments, when xc1 in Formula 401 is two or more, twoA₄₀₁(s) in two or more L₄₀₁(s) may be optionally linked via X₄₀₇, whichis a linking group, or two A₄₀₂(s) in two or more L₄₀₁(s) may beoptionally linked via X₄₀₈, which is a linking group (see Compounds PD1to PD4 and PD7). X₄₀₇ and X₄₀₈ may each independently be a single bond,*—O—*′, *—S—*′, *—C(═O)—*′, *—N(Q₄₁₃)-*′, *—C(Q₄₁₃)(Q₄₁₄)-*′, or*—C(Q₄₁₃)═C(Q₄₁₄)-*′ (wherein Q₄₁₃ and Q₄₁₄ may each independently behydrogen, deuterium, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a biphenyl group, a terphenyl group, or a naphthyl group).

L₄₀₂ in Formula 401 may be a monovalent, divalent, or trivalent organicligand. For example, L₄₀₂ may be selected from halogen, diketone (forexample, acetylacetonate), carboxylic acid (for example, picolinate),—C(═O) isonitrile, —CN, and phosphorus (for example, phosphine, orphosphite).

In one or more embodiments, the phosphorescent dopant may be selectedfrom, for example, Compounds PD1 to PD25:

The fluorescent dopant may include an arylamine compound or astyrylamine compound.

The fluorescent dopant may include a compound represented by Formula 501below:

In Formula 501,

Ar₅₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group ora substituted or unsubstituted C₁-C₆₀ heterocyclic group,

L₅₀₁ to L₅₀₃ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

xd1 to xd3 may each independently be an integer of 0 to 3;

R₅₀₁ and R₅₀₂ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedheterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group,and

xd4 may be an integer of 1 to 6.

In one embodiment, Ar_(5o1) in Formula 501 may be selected from

a naphthalene group, a heptalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, naphthacene group, a picene group, a perylene group, a pentaphenegroup, an indenoanthracene group, and an indenophenanthrene group; and

a naphthalene group, a heptalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, naphthacene group, a picene group, a perylene group, a pentaphenegroup, an indenoanthracene group, and an indenophenanthrene group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and anaphthyl group.

In one or more embodiments, L₅₀₁ to L₅₀₃ in Formula 501 may eachindependently be selected from

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group,dibenzosilolylene group, a pyridinylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, and a pyridinylene group, each substituted withat least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, and a pyridinyl group.

In one or more embodiments, R₅₀₁ and R₅₀₁ in Formula 502 may eachindependently be selected from

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, and a pyridinyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, and a pyridinyl group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenylgroup, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, and —Si(Q₃₁)(Q₃₂)(Q₃₃),

wherein Q₃₁ to Q₃₃ may each be selected from a C₁-C₁₀ alkyl group, aC₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

In one or more embodiments, xd4 in Formula 501 may be 2.

For example, the fluorescent dopant may be selected from Compounds FD1to FD22:

In one or more embodiments, the fluorescent dopant may be selected fromthe following compounds.

The electron transport region may have i) a single-layered structureincluding a single layer including a single material, ii) asingle-layered structure including a single layer including a pluralityof different materials, or iii) a multi-layered structure having aplurality of layers including a plurality of different materials.

The electron transport region may include at least one selected from abuffer layer, a hole blocking layer, an electron control layer, anelectron transport layer, and an electron injection layer.

For example, the electron transport region may have an electrontransport layer/electron injection layer structure, a hole blockinglayer/electron transport layer/electron injection layer structure, anelectron control layer/electron transport layer/electron injection layerstructure, or a buffer layer/electron transport layer/electron injectionlayer structure, wherein for each structure, constituting layers aresequentially stacked from an emission layer.

The electron transport region (for example, a buffer layer, a holeblocking layer, an electron control layer, or an electron transportlayer in the electron transport region) may include a metal-freecompound containing at least one π electron-depleted nitrogen-containingring.

The “at electron-depleted nitrogen-containing ring” indicates a C₁-C₆₀heterocyclic group having at least one *—N═*′ moiety as a ring-formingmoiety.

For example, the “π electron-depleted nitrogen-containing ring” may bei) a 60-membered to 7-membered hetero monocyclic group having at leastone *—N═*′ moiety, ii) a heteropoly cyclic group in which two or more5-membered to 7-membered hetero monocyclic groups each having at leastone *—N═*′ moiety are condensed with each other, or iii) a heteropolycyclic group in which at least one of 5-membered to 7-membered heteromonocyclic groups, each having at least one *—N═*′ moiety, is condensedwith at least one C₅-C₆₀ carbocyclic group.

Examples of the π electron-depleted nitrogen-containing ring include animidazole, a pyrazole, a thiazole, an isothiazole, an oxazole, anisoxazole, a pyridine, a pyrazine, a pyrimidine, a pyridazine, anindazole, a purine, a quinoline, an isoquinoline, a benzoquinoline, aphthalazine, a naphthyridine, a quinoxaline, a quinazoline, a cinnoline,a phenanthridine, an acridine, a phenanthroline, a phenazine, abenzimidazole, an isobenzothiazole, a benzoxazole, an isobenzoxazole, atriazole, a tetrazole, an oxadiazole, a triazine, thiadiazol, animidazopyridine, an imidazopyrimidine, and an azacarbazole.

In one embodiment, the electron transport region may further include, inaddition to the heterocyclic compound represented by Formula 1, acompound represented by Formula 601.[Ar₆₀₁]_(xe11)-[(L₆₀₁)_(xe1)-R₆₀₁]_(xe21).  <Formula 601>

In Formula 601,

Ar₆₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group ora substituted or unsubstituted C₁-C₆₀ heterocyclic group,

xe11 may be 1, 2, or 3,

L₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group;

xe1 may be an integer selected from 0 to 5,

R₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, a substituted or unsubstituted monovalent non-aromaticcondensed heteropolycyclic group, —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃), —C(═O)(Q₆₀₁),—S(═O)₂(Q₆₀₁) and —P(═O)(Q₆₀₁)(Q₆₀₂),

wherein Q₆₀₁ to Q₆₀₃ may each independently be a C₁-C₁₀ alkyl group, aC₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, or a naphthyl group, and

xe21 may be an integer selected from 1 to 5.

In one embodiment, at least one of Ar₆₀₁(s) in the number of xe11 and/orat least one of R₆₀₁(s) in the number of xe21 may include the πelectron-depleted nitrogen-containing ring.

In one embodiment, ring Ar₆₀₁ in Formula 601 may be selected from:

a benzene group, a naphthalene group, a fluorene group, aSpiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, naphthacene group, a picene group, a perylene group, a pentaphenegroup, an indenoanthracene group, a dibenzofuran group, adibenzothiophene group, a carbazole group, an imidazole group, apyrazole group, a thiazole group, an isothiazole group, an oxazolegroup, an isoxazole group, a pyridine group, a pyrazine group, apyrimidine group, a pyridazine group, an indazole group, a purine group,a quinoline group, an isoquinoline group, a benzoquinoline group, aphthalazine group, naphthyridine group, a quinoxaline group, aquinazoline group, a cinnoline group, a phenanthridine group, anacridine group, phenanthroline group, phenazine group, a benzimidazolegroup, an isobenzothiazole group, a benzoxazole group, an isobenzoxazolegroup, a triazole group, a tetrazole group, an oxadiazole group, atriazine group, thiadiazol group, an imidazopyridine group, animidazopyrimidine group, and an azacarbazole group; and

a benzene group, a naphthalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, naphthacene group, a picene group, a perylene group, a pentaphenegroup, an indenoanthracene group, a dibenzofuran group, adibenzothiophene group, a carbazole group, an imidazole group, apyrazole group, a thiazole group, an isothiazole group, an oxazolegroup, an isoxazole group, a pyridine group, a pyrazine group, apyrimidine group, a pyridazine group, an indazole group, a purine group,a quinoline group, an isoquinoline group, a benzoquinoline group, aphthalazine group, naphthyridine group, a quinoxaline group, aquinazoline group, a cinnoline group, a phenanthridine group, anacridine group, phenanthroline group, phenazine group, a benzimidazolegroup, an isobenzothiazole group, a benzoxazole group, an isobenzoxazolegroup, a triazole group, a tetrazole group, an oxadiazole group, atriazine group, thiadiazol group, an imidazopyridine group, animidazopyrimidine group, and an azacarbazole group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a biphenyl group, a terphenyl group, a naphthyl group,—Si(Q₃₁)(Q₃₂)(Q₃₃), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group.

When xe11 in Formula 601 is two or more, two or more Ar₆₀₁(s) may belinked via a single bond.

In one or more embodiments, Ar₆₀₁ in Formula 601 may be an anthracenegroup.

In one or more embodiments, a compound represented by Formula 601 may berepresented by Formula 601-1:

In Formula 601-1,

X₆₁₄ may be N or C(R₆₁₄), X₆₁₅ may be N or C(R₆₁₅), X₆₁₆ may be N orC(R₆₁₆), and at least one selected from X₆₁₄ to X₆₁₆ may be N,

L₆₁₁ to L₆₁₃ may be each independently substantially the same asdescribed in connection with L₆₀₁,

xe611 to xe613 may be each independently substantially the same asdescribed in connection with xe1,

R₆₁₁ to R₆₁₃ may be each independently substantially the same asdescribed in connection with R₆₀₁,

R₆₁₄ to R₆₁₆ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group.

In one embodiment, L₆₀₁ and L₆₁₁ to L₆₁₃ in Formulae 601 and 601-1 mayeach independently be selected from

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group,dibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group,dibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, anaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group,an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenylgroup, a hexacenyl group, a pentacenyl group, a thiophenyl group, afuranyl group, a carbazolyl group, an indolyl group, an isoindolylgroup, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranylgroup, a dibenzothiophenyl group, a benzocarbazolyl group, adibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, anoxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, aphenanthridinyl group, an acridinyl group, a phenanthrolinyl group, aphenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, abenzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinylgroup, and an azacarbazolyl group.

In one or more embodiments, xe1 and xe611 to xe613 in Formulae 601 and601-1 may each independently be 0, 1, or 2.

In one or more embodiments, R₆₀₁ and R₆₁₁ to R₆₁₃ in Formula 601 and601-1 may each independently be selected from

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group;

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, aperylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a thiophenyl group, a furanyl group, a carbazolyl group, anindolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group; and—S(═O)₂(Q₆₀₁), and —P(═O)(Q₆₀₁)(Q₆₀₂),

wherein Q₆₀₁ and Q₆₀₂ are substantially the same as described above.

The electron transport region may include at least one compound selectedfrom Compounds ET1 to ET36:

In one or more embodiments, the electron transport region may include atleast one selected from 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline(BCP), 4,7-dphenyl-1,10-phenanthroline (Bphen), Alq₃, BAlq,3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole(TAZ), and NTAZ.

A thickness of the buffer layer, the hole blocking layer, or theelectron control layer may be in a range of about 20 Å to about 1,000 Å,for example, about 30 Å to about 300 Å. When the thicknesses of thebuffer layer, the hole blocking layer, and the electron control layerare within these ranges, the electron blocking layer may have excellentelectron blocking characteristics or electron control characteristicswithout a substantial increase in driving voltage.

A thickness of the electron transport layer may be in a range of about100 Å to about 1,000 Å, e.g., about 150 Å to about 500 Å. When thethickness of the electron transport layer is within the range describedabove, the electron transport layer may have satisfactory electrontransport characteristics without a substantial increase in drivingvoltage.

The electron transport region (for example, the electron transport layerin the electron transport region) may further include, in addition tothe materials described above, a metal-containing material.

The metal-containing material may include at least one selected fromalkali metal complex and alkaline earth-metal complex. The alkali metalcomplex may include a metal ion selected from an Li ion, a Na ion, a Kion, a Rb ion, and a Cs ion, and the alkaline earth-metal complex mayinclude a metal ion selected from a Be ion, a Mg ion, a Ca ion, an Srion, and a Ba ion. A ligand coordinated with the metal ion of the alkalimetal complex or the alkaline earth-metal complex may be selected from ahydroxy quinoline, a hydroxy isoquinoline, a hydroxy benzoquinoline, ahydroxy acridine, a hydroxy phenanthridine, a hydroxy phenylan oxazole,a hydroxy phenylthiazole, a hydroxy diphenylan oxadiazole, a hydroxydiphenylthiadiazol, a hydroxy phenylpyridine, a hydroxyphenylbenzimidazole, a hydroxy phenylbenzothiazole, a bipyridine, aphenanthroline, and a cyclopentadiene.

For example, the metal-containing material may include a Li complex. TheLi complex may include, e.g., Compound ET-D1 (lithium quinolate, LiQ) orET-D2.

The electron transport region may include an electron injection layerthat facilitates injection of electrons from the second electrode 190.The electron injection layer may directly contact the second electrode190.

The electron injection layer may have i) a single-layered structureincluding a single layer including a single material, ii) asingle-layered structure including a single layer including a pluralityof different materials, or iii) a multi-layered structure having aplurality of layers including a plurality of different materials.

The electron injection layer may include alkali metal, alkaline earthmetal, rare-earth metal, alkali metal compound, alkaline earth-metalcompound, rare-earth metal compound, alkali metal complex, alkalineearth-metal complex, rare-earth metal complex, or any combinationsthereof.

The alkali metal may be selected from Li, Na, K, Rb, and a Cs. In oneembodiment, the alkali metal may be Li, Na, or Cs. In one or moreembodiments, the alkali metal may be Li or Cs.

The alkaline earth metal may be selected from Mg, Ca, Sr, and Ba.

The rare-earth metal may be selected from Sc, Y, Ce, Yb, Gd, and Tb.

The alkali metal compound, the alkaline earth-metal compound, and therare-earth metal compound may be selected from oxides and halides (forexample, fluorides, chlorides, bromides, or iodides) of the alkalimetal, the alkaline earth-metal and rare-earth metal.

The alkali metal compound may be selected from alkali metal oxides, suchas Li₂O, Cs₂O, or K₂O, and alkali metal halides, such as LiF, NaF, CsF,KF, LiI, NaL CsI, KI, or RbI. In one embodiment, the alkali metalcompound may be selected from LiF, Li₂O, NaF, LiI, NaI, CsI, and KI.

The alkaline earth-metal compound may be selected from alkalineearth-metal compounds, such as BaO, SrO, CaO, Ba_(x)Sr_(1-x)O (0<x<1),or Ba_(x)Ca_(1-x)O (0<x<1). In one embodiment, the alkaline earth-metalcompound may be selected from BaO, SrO, and a CaO.

The rare-earth metal compound may be selected from YbF₃, ScF₃, ScO₃,Y₂O₃, Ce₂O₃, GdF₃, and TbF₃. In one embodiment, the rare-earth metalcompound may be selected from YbF₃, ScF₃, TbF₃, YbI₃, ScI₃, and TbI₃.

The alkali metal complex, the alkaline earth-metal complex, and therare-earth metal complex may include an ion of alkali metal, alkalineearth-metal, and rare-earth metal as described above, and a ligandcoordinated with a metal ion of the alkali metal complex, the alkalineearth-metal complex, and the rare-earth metal complex may eachindependently be selected from hydroxy quinoline, hydroxy isoquinoline,hydroxy benzoquinoline, hydroxy acridine, hydroxy phenanthridine,hydroxy phenylan oxazole, hydroxy phenylthiazole, hydroxy diphenylanoxadiazole, hydroxy diphenylthiadiazol, hydroxy phenylpyridine, hydroxyphenylbenzimidazole, hydroxy phenylbenzothiazole, bipyridine,phenanthroline, and cyclopentadiene.

The electron injection layer may consist of alkali metal, alkaline earthmetal, rare-earth metal, an alkali metal compound, an alkalineearth-metal compound, a rare-earth metal compound, an alkali metalcomplex, an alkaline earth-metal complex, a rare-earth metal complex, orany combinations thereof, as described above. In one or moreembodiments, the electron injection layer may further include an organicmaterial. When the electron injection layer further includes an organicmaterial, alkali metal, alkaline earth metal, rare-earth metal, alkalimetal compound, alkaline earth-metal compound, rare-earth metalcompound, alkali metal complex, alkaline earth-metal complex, rare-earthmetal complex, or any combinations thereof may be homogeneously ornon-homogeneously dispersed in a matrix including the organic material.

A thickness of the electron injection layer may be in a range of about 1Å to about 100 Å, for example, about 3 Å to about 90 Å. When thethickness of the electron injection layer is within the range describedabove, the electron injection layer may have satisfactory electroninjection characteristics without a substantial increase in drivingvoltage.

The second electrode 190 may be disposed on the organic layer 150 havingsuch a structure. The second electrode 190 may be a cathode which is anelectron injection electrode, and in this regard, a material for formingthe second electrode 190 may be selected from metal, an alloy, anelectrically conductive compound, and a mixture thereof, which have arelatively low work function.

The second electrode 190 may include at least one selected from lithium(Li), silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium(Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver(Mg—Ag), ITO, and IZO. The second electrode 190 may be a transmissiveelectrode, a semi-transmissive electrode, or a reflective electrode.

The second electrode 190 may have a single-layered structure, or amulti-layered structure including two or more layers.

An organic light-emitting device 20 of FIG. 2 includes a first cappinglayer 210, a first electrode 110, an organic layer 150, and a secondelectrode 190 which are sequentially stacked in this stated order, anorganic light-emitting device 30 of FIG. 3 includes a first electrode110, an organic layer 150, a second electrode 190, and a second cappinglayer 220 which are sequentially stacked in this stated order, and anorganic light-emitting device 40 of FIG. 4 includes a first cappinglayer 210, a first electrode 110, an organic layer 150, a secondelectrode 190, and a second capping layer 220.

Regarding FIGS. 2 to 4, the first electrode 110, the organic layer 150,and the second electrode 190 may be understood by referring to thedescription presented in connection with FIG. 1.

In the organic layer 150 of each of the organic light-emitting devices20 and 40, light generated in an emission layer may pass through thefirst electrode 110, which is a semi-transmissive electrode or atransmissive electrode, and the first capping layer 210 toward theoutside, and in the organic layer 150 of each of the organiclight-emitting devices 30 and 40, light generated in an emission layermay pass through the second electrode 190, which is a semi-transmissiveelectrode or a transmissive electrode, and the second capping layer 220toward the outside.

The first capping layer 210 and the second capping layer 220 mayincrease external luminescent efficiency according to the principle ofconstructive interference.

The first capping layer 210 and the second capping layer 220 may eachindependently be an organic capping layer including an organic material,an inorganic capping layer including an inorganic material, or acomposite capping layer including an organic material and an inorganicmaterial.

At least one selected from the first capping layer 210 and the secondcapping layer 220 may each independently include at least one materialselected from carbocyclic compounds, heterocyclic compounds, amine-basedcompounds, porphyrine derivatives, phthalocyanine derivatives,naphthalocyanine derivatives, alkali metal complexes, and alkalineearth-based complexes. The carbocyclic compound, the heterocycliccompound, and the amine-based compound may be optionally substitutedwith a substituent containing at least one element selected from O, N,S, Se, Si, F, Cl, Br, and I. In one embodiment, at least one selectedfrom the first capping layer 210 and the second capping layer 220 mayeach independently include an amine-based compound.

In one embodiment, at least one selected from the first capping layer210 and the second capping layer 220 may each independently include thecompound represented by Formula 201 or the compound represented byFormula 202.

In one or more embodiments, at least one selected from the first cappinglayer 210 and the second capping layer 220 may each independentlyinclude a compound selected from Compounds HT28 to HT33 and a CompoundsCP1 to CP5.

Hereinbefore, the organic light-emitting device according to anembodiment has been described in connection with FIGS. 1-4.

Layers constituting the hole transport region, an emission layer, andlayers constituting the electron transport region may be formed in acertain region by using one or more suitable methods selected fromvacuum deposition, spin coating, casting, langmuir-blodgett (LB)deposition, ink-jet printing, laser-printing, and laser-induced thermalimaging.

When layers constituting the hole transport region, an emission layer,and layers constituting the electron transport region are formed byvacuum deposition, for example, the vacuum deposition may be performedat a deposition temperature of about 100 to about 500° C., at a vacuumdegree of about 10⁻⁸ to about 10⁻³ torr, and at a deposition rate ofabout 0.01 to about 100 Å/sec by taking into account a compound to beincluded in a layer to be formed, and the structure of a layer to beformed.

When layers constituting the hole transport region, an emission layer,and layers constituting the electron transport region are formed by spincoating, the spin coating may be performed at a coating speed of about2,000 rpm to about 5,000 rpm and at a heat treatment temperature ofabout 80° C. to 200° C. by taking into account a compound to be includedin a layer to be formed, and the structure of a layer to be formed.

The term “C₁-C₆₀ alkyl group” as used herein refers to a linear orbranched aliphatic saturated hydrocarbon monovalent group having 1 to 60carbon atoms, and examples thereof include a methyl group, an ethylgroup, a propyl group, an isobutyl group, a sec-butyl group, atert-butyl group, a pentyl group, an iso-amyl group, and a hexyl group.The term “C₁-C₆₀ alkylene group” used herein refers to a divalent grouphaving the same structure as the C₁-C₆₀ alkyl group.

The term “C₂-C₆₀ alkenyl group” as used herein refers to a hydrocarbongroup formed by substituting at least one carbon-carbon double bond inthe middle or at the terminus of the C₂-C₆₀ alkyl group, andnon-limiting examples thereof include an ethenyl group, a propenylgroup, and a butenyl group. The term “C₂-C₆₀ alkenylene group” as usedherein refers to a divalent group having the same structure as theC₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein refers to a hydrocarbongroup formed by substituting at least one carbon-carbon triple bond inthe middle or at the terminus of the C₂-C₆₀ alkyl group, andnon-limiting examples thereof include an ethynyl group, and a propynylgroup. The term “C₂-C₆₀ alkynylene group” as used herein refers to adivalent group having the same structure as the C₂-C₆₀ alkynyl group.

The term “C₁-C₆₀ alkoxy group” as used herein refers to a monovalentgroup represented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group),and examples thereof include a methoxy group, an ethoxy group, and anisopropyloxy group.

The term “C₃-C₁₀ cycloalkyl group” as used herein refers to a monovalentsaturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, andnon-limiting examples thereof include a cyclopropyl group, a cyclobutylgroup, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group:The term “C₃-C₁₀ cycloalkylene group” as used herein refers to adivalent group having the same structure as the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group” as used herein refers to amonovalent saturated monocyclic group having at least one heteroatomselected from N, O, Si, P, and S as a ring-forming atom and 1 to 10carbon atoms, and non-limiting examples thereof include a1,2,3,4-oxatriazolidinyl group, a tetrahydrofuranyl group, and atetrahydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkylene group”as used herein refers to a divalent group having the same structure asthe C₁-C₁₀ heterocycloalkyl group.

The term “C₃-C₁₀ cycloalkenyl group” as used herein refers to amonovalent monocyclic group that has 3 to 10 carbon atoms and at leastone carbon-carbon double bond in the ring thereof and does not havearomaticity, and non-limiting examples thereof include a cyclopentenylgroup, a cyclohexenyl group, and a cycloheptenyl group. The term “C₃-C₁₀cycloalkenylene group” as used herein refers to a divalent group havingthe same structure as the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein refers to amonovalent monocyclic group that has at least one heteroatom selectedfrom N, O, Si, P, and S as a ring-forming atom, 1 to 10 carbon atoms,and at least one carbon-carbon double bond in its ring. Non-limitingexamples of the C₁-C₁₀ heterocycloalkenyl group are a4,5-dihydro-1,2,3,4-oxatriazolyl group, a 2,3-dihydrofuranyl group and a2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylenegroup” as used herein refers to a divalent group having the samestructure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein refers to a monovalent grouphaving a carbocyclic aromatic system having 6 to 60 carbon atoms, andthe term “C₆-C₆₀ arylene group” as used herein refers to a divalentgroup having a carbocyclic aromatic system having 6 to 60 carbon atoms.Non-limiting examples of the C₆-C₆₀ aryl group include a phenyl group, anaphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenylgroup, and a chrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀arylene group each include two or more rings, the rings may be fused toeach other.

The term “C₁-C₆₀ heteroaryl group” as used herein refers to a monovalentgroup having a heterocyclic aromatic system that has at least oneheteroatom selected from N, O, P, and S as a ring-forming atom, and 1 to60 carbon atoms. The term “C₁-C₆₀ heteroarylene group” as used hereinrefers to a divalent group having a heterocyclic aromatic system thathas at least one heteroatom selected from N, O, P, and S as aring-forming atom, and 1 to 60 carbon atoms. Non-limiting examples ofthe C₁-C₆₀ heteroaryl group include a pyridinyl group, a pyrimidinylgroup, a pyrazinyl group, a pyridazinyl group, a triazinyl group, aquinolinyl group, and an isoquinolinyl group. When the C₁-C₆₀ heteroarylgroup and the C₁-C₆₀ heteroarylene group each include two or more rings,the rings may be condensed with each other.

The term “C₆-C₆₀ aryloxy group” as used herein refers to —OA₁₀₂ (whereinA₁₀₂ is the C₆-C₆₀ aryl group), and a C₆-C₆₀ arylthio group used hereinindicates —SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group).

The term “monovalent non-aromatic condensed polycyclic group” as usedherein refers to a monovalent group (for example, having 8 to 60 carbonatoms) that has two or more rings condensed with each other, only carbonatoms as a ring-forming atom, and non-aromaticity in the entiremolecular structure. A detailed example of the monovalent non-aromaticcondensed polycyclic group is a fluorenyl group. The term “divalentnon-aromatic condensed polycyclic group,” used herein, refers to adivalent group having the same structure as the monovalent non-aromaticcondensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” asused herein refers to a monovalent group (for example, having 1 to 60carbon atoms) that has two or more rings condensed to each other, has atleast one heteroatom selected from N, O, Si, P, and S, other than carbonatoms, as a ring-forming atom, and has non-aromaticity in the entiremolecular structure. An example of the monovalent non-aromatic condensedheteropolycyclic group is a carbazolyl group. The term “divalentnon-aromatic condensed heteropolycyclic group,” used herein, refers to adivalent group having the same structure as the monovalent non-aromaticcondensed heteropolycyclic group.

The term “C₅-C₆₀ carbocyclic group” as used herein refers to amonocyclic or polycyclic group having 5 to 60 carbon atoms in which aring-forming atom is a carbon atom only. The C₅-C₆₀ carbocyclic groupmay be an aromatic carbocyclic group or a non-aromatic carbocyclicgroup. The C₅-C₆₀ carbocyclic group may be a ring, such as a benzenegroup; a monovalent group, such as a phenyl group; or a divalent group,such as a phenylene group. In one or more embodiments, depending on thenumber of substituents connected to the C₅-C₆₀ carbocyclic group, theC₅-C₆₀ carbocyclic group may be a trivalent group or a quadrivalentgroup.

The term “C₁-C₆₀ heterocyclic group” as used herein refers to a grouphaving the same structure as the C₁-C₆₀ carbocyclic group, except thatas a ring-forming atom, at least one heteroatom selected from N, O, Si,P, and S is used in addition to carbon (the number of carbon atoms maybe in a range of 1 to 60).

At least one of substituents of the substituted C₅-C₆₀ carbocyclicgroup, substituted C₁-C₆₀ heterocyclic group, substituted C₃-C₁₀cycloalkylene group, substituted C₁-C₁₀ heterocycloalkylene group,substituted C₃-C₁₀ cycloalkenylene group, substituted C₁-C₁₀heterocycloalkenylene group, substituted C₆-C₆₀ arylene group,substituted C₁-C₆₀ heteroarylene group, substituted divalentnon-aromatic condensed polycyclic group, substituted divalentnon-aromatic condensed heteropolycyclic group, substituted C₁-C₆₀ alkylgroup, substituted C₂-C₆₀ alkenyl group, substituted C₂-C₆₀ alkynylgroup, substituted C₁-C₆₀ alkoxy group, substituted C₃-C₁₀ cycloalkylgroup, substituted C₁-C₁₀ heterocycloalkyl group, substituted C₃-C₁₀cycloalkenyl group, substituted C₁-C₁₀ heterocycloalkenyl group,substituted C₆-C₆₀ aryl group, substituted C₆-C₆₀ aryloxy group,substituted C₆-C₆₀ arylthio group, substituted C₁-C₆₀ heteroaryl group,substituted monovalent non-aromatic condensed polycyclic group, andsubstituted monovalent non-aromatic condensed heteropolycyclic group maybe selected from

deuterium (-D), —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, anda C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group,—Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁),—S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-Cooheteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₁₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃),—N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and—P(═O)(Q₂₁)(Q₂₂); and

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₁ to Q₆, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃ and Q₃₁ to Q₃₃ may eachindependently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group.

The term “Ph” used herein refers to a phenyl group, the term “Me” usedherein refers to a methyl group, the term “Et” used herein refers to anethyl group, the term “ter-Bu” or “Bu^(t)” used herein refers to atert-butyl, and the term “OMe” used herein refers to a methoxy group.

The term “biphenyl group” as used therein refers to “a phenyl groupsubstituted with a phenyl group.” In other words, a “biphenyl group” isa substituted phenyl group having a C6-C60 aryl group as a substituent.

The term “terphenyl group” as used herein refers to “a phenyl groupsubstituted with a biphenyl group.” In other words, the “terphenylgroup” is a substituted phenyl group having, as a substituent, a C₆-C₆₀aryl group substituted with a C₆-C₆₀ aryl group.

* and *′ used herein, unless defined otherwise, each refer to a bindingsite to a neighboring atom in a corresponding formula.

Hereinafter, a compound according to embodiments and an organiclight-emitting device according to embodiments will be described indetail with reference to Synthesis Examples and Examples. The wording “Bwas used instead of A” used in describing Synthesis Examples refers tothat an identical molar equivalent of B was used in place of A.

The following Examples and Comparative Examples are provided in order tohighlight characteristics of one or more embodiments, but it will beunderstood that the Examples and Comparative Examples are not to beconstrued as limiting the scope of the embodiments, nor are theComparative Examples to be construed as being outside the scope of theembodiments. Further, it will be understood that the embodiments are notlimited to the particular details described in the Examples andComparative Examples.

EXAMPLE Synthesis Example 1: Synthesis of Compound 1

Synthesis of Intermediate 1-1

2,5-dibromopyridine and thiophenol were reacted with NaOtBu intetrahydrofuran (THF) to obtain Intermediate 1-1. Intermediate 1-1 wasconfirmed by LC-MS.

C₁₁H₈BrNS: M+1 265.9

Synthesis of Intermediate 1-2

Intermediate 1-1 was oxidized in methylene chloride (MC) by usingm-chloroperoxybenzoic acid (mCPBA) to obtain Intermediate 1-2.Intermediate 1-2 was confirmed by LC-MS.

C₁₁H₈BrNO₂S: M+1 297.9

Synthesis of Compound 1

3.4 g of Intermediate 1-2, 2.4 g of 9,9-dimethyl-9,10-dihydroacridine,0.077 g of palladium (II) acetate, 0.18 g of triphenylphosphine, and 1.6g of NaOtBu were dissolved in 60 mL of toluene, and then, the mixturewas refluxed for 3 hours. The obtained reaction solution was cooled toambient temperature, and then, an organic layer was extracted therefromby using ethyl acetate (EA), and washed with water. Then, the collectedorganic layer was dried by using magnesium sulfate, and the residueobtained by evaporating a solvent therefrom was separation-purified bysilica gel column chromatography, thereby completing the preparation of3.0 g (yield: 62%) of Compound 1. Compound 1 was confirmed by LC-MS and¹H NMR.

C₂₆H₂₂N₂O₂S: M+1 427.2

¹H NMR (500 MHz, CDCl₃) δ=8.07-8.03 (m, 3H), 7.93 (t, 1H), 7.82 (s, 1H),7.75 (t, 2H), 7.27-7.14 (m, 7H), 6.95 (t, 2H), 1.71 (s, 6H).

Synthesis Example 2: Synthesis of Compound 19

Synthesis of Intermediate 19-1

Intermediate 19-1 was prepared in the same manner as used to synthesizeIntermediate 1-1, except that 3,6-dibromo-2-methylpyridine was usedinstead of 2,5-dibromopyridine, and pyridine-3-thiol was used instead ofthiophenol. Intermediate 19-1 was confirmed by LC-MS.

C₁₂H₁₀BrNS: M+1 280.9

Synthesis of Intermediate 19-2

Intermediate 19-2 was prepared in the same manner as used to synthesizeIntermediate 1-2, except that Intermediate 19-1 was used instead ofIntermediate 1-1. Intermediate 19-2 was confirmed by LC-MS.

C₁₂H₁₀BrNO₂S: M+1 311.9

Synthesis of Compound 19

2.8 g (yield: 55%) of Compound 19 was prepared in the same manner asused to synthesize Compound 1, except that Intermediate 19-2 was usedinstead of Intermediate 1-2. Compound 19 was confirmed by LC-MS and ¹HNMR.

C₂₇H₂₄N₂O₂S: M+1 441.1

¹H NMR (500 MHz, CDCl₃) δ=8.86 (s, 1H), 8.51 (d, 1H), 8.39 (d, 1H),7.67-7.48 (m, 4H), 7.19-7.14 (m, 6H), 6.92 (t, 2H), 2.13 (s, 3H), 1.68(s, 6H).

Synthesis Example 3: Synthesis of Compound 26

Synthesis of Intermediate 26-1

Intermediate 26-1 was prepared in the same manner as used to synthesizeIntermediate 1-1, except that 3,6-dibromo-2-methylpyridine was usedinstead of 2,5-dibromopyridine. Intermediate 26-1 was confirmed byLC-MS.

C₁₂H₁₀BrNS: M+1 280.8

Synthesis of Intermediate 26-2

Intermediate 26-2 was prepared in the same manner as used to synthesizeIntermediate 1-2, except that Intermediate 26-1 was used instead ofIntermediate 1-1. Intermediate 26-2 was confirmed by LC-MS.

C₁₂H₁₀BrNO₂S: M+1 312.0

Synthesis of Compound 26

2.6 g (yield: 49%) of Compound 26 was prepared in the same manner asused to synthesize Compound 1, except that Intermediate 26-2 was usedinstead of Intermediate 1-2. Compound 26 was confirmed by LC-MS and ¹HNMR.

C₂₇H₂₄N₂O₂S: M+1 441.2

¹H NMR (500 MHz, CDCl₃) δ=8.07 (d, 2H), 7.93 (t, 1H), 7.87 (d, 1H), 7.75(t, 2H), 7.24 (d, 1H), 7.21-7.13 (m, 6H), 6.97 (t, 2H), 2.49 (s, 3H),1.69 (s, 6H).

Synthesis Example 4: Synthesis of Compound 31

Synthesis of Intermediate 31-1

2-bromo-9,9-dimethyl-9,10-dihydroacridine (CAS: 1443680-94-1) wasreacted with tosyl chloride (TsCl) under a basic condition to obtainIntermediate 31-1. Intermediate 31-1 was confirmed by LC-MS.

C₂₂H₂₀BrNO₂S M+1: 442.1

Synthesis of Intermediate 31-2

Compound 31-1 was reacted with carbazole in the presence of a coppercatalyst to obtain Intermediate 31-2. Intermediate 31-2 was confirmed byLC-MS.

C₃₄H₂₈N₂O₂S M+1: 529.3

Synthesis of Intermediate 31-3

An acid was added to Compound 31-2 to obtain Intermediate 31-3.Intermediate 31-3 was confirmed by LC-MS.

C₂₇H₂₂N₂ M+1: 375.2

Synthesis of Compound 31

4.2 g of Compound 31-3, 3.5 g of Compound 26-3, 0.075 g of palladium(II) acetate, 0.18 g of triphenylphosphine, and 1.6 g of NaOtBu weredissolved in 60 mL of toluene, and the mixture was refluxed for 3 hours.The obtained reaction solution was cooled to ambient temperature, and anorganic layer was extracted therefrom by using EA, and washed withwater. Then, the collected organic layer was dried by using magnesiumsulfate, and the residue obtained by evaporating a solvent therefrom wasseparation-purified by silica gel column chromatography, therebycompleting the preparation of 5.2 g (yield: 77%) of Compound 31.Compound 31 was confirmed by LC-MS and ¹H-NMR.

C₃₉H₃₁N₃O₂S M+1: 606.1

¹H NMR (500 MHz, CDCl₃) δ=8.18 (d, 2H), 8.06 (d, 2H), 7.93 (t, 1H), 7.87(d, 1H), 7.76-7.73 (m, 3H), 7.60-7.54 (m, 3H), 7.5 (t, 2H), 7.31 (d,1H), 7.26 (d, 1H), 7.22-7.13 (m, 6H), 6.99 (t, 1H), 2.48 (s, 3H), 1.66(s, 6H).

Synthesis Example 5: Synthesis of Compound 32

Synthesis of Intermediate 32-1

2,7-dibromo-9,9-dimethyl-9,10-dihydroacridine (CAS: 1333316-35-0) wasreacted with TsCl under a basic condition to obtain Intermediate 32-1.Intermediate 32-1 was confirmed by LC-MS.

C₂₂H₁₉Br₂NO₂S M+1: 519.8

Synthesis of Intermediate 32-2

Intermediate 32-1 was reacted with carbazole in the presence of a coppercatalyst to obtain Intermediate 32-2. Intermediate 32-2 was confirmed byLC-MS.

C₄₆H₃₅N₃O₂S M+1: 694.3

Synthesis of Intermediate 32-3

An acid was added to Intermediate 32-2 to obtain Intermediate 32-3.

Intermediate 32-3 was confirmed by LC-MS.

C₃₉H₂₉N₃ M+1: 539.1

Synthesis of Compound 32

2.9 g of Intermediate 32-3, 1.7 g of Intermediate 26-3, 0.036 g ofpalladium (II) acetate, 0.085 g of triphenylphosphine, and 0.78 g ofNaOtBu were dissolved in 30 mL of toluene, and the mixture was refluxedfor 3 hours. The obtained reaction solution was cooled to ambienttemperature, and an organic layer was extracted therefrom by using EA,and washed with water. Then, the collected organic layer was dried byusing magnesium sulfate, and the residue obtained by evaporating asolvent therefrom was separation-purified by silica gel columnchromatography, thereby completing the preparation of 2.5 g (yield: 61%)of Compound 32. Compound 32 was confirmed by LC-MS and ¹H-NMR.

C₅₁H₃₈N₄O₂S M+1: 771.2

¹H NMR (500 MHz, CDCl₃) δ=8.21 (d, 4H), 8.04 (d, 2H), 7.94 (t, 1H), 7.88(d, 1H), 7.76-7.73 (m, 4H), 7.59-7.54 (m, 6H), 7.51 (t, 4H), 7.32 (d,2H), 7.27 (d, 1H), 7.22 (t, 4H), 2.48 (s, 3H), 1.71 (s, 6H).

Synthesis Example 6: Synthesis of Compound 41

Synthesis of Intermediate 41-1

2,7-dibromo-9,9-dimethyl-9,10-dihydroacridine (CAS: 1333316-35-0) wasreacted with phenylboronic acid in the presence of a palladium catalystto obtain Intermediate 41-1. Intermediate 41-1 was confirmed by LC-MS.

C₂₇H₂₃N M+1: 362.1

Synthesis of Compound 41

Intermediate 41-1 2.7 g, 2.3 g of Intermediate 26-3, 0.050 g ofpalladium (II) acetate, 0.12 g of triphenylphosphine, and 1.0 g ofNaOtBu were dissolved in 40 mL of toluene, and then, the mixture wasrefluxed for 3 hours. The obtained reaction solution was cooled toambient temperature, and an organic layer was extracted therefrom byusing EA, and washed with water. Then, the collected organic layer wasdried by using magnesium sulfate, and the residue obtained byevaporating a solvent therefrom was separation-purified by silica gelcolumn chromatography, thereby completing the preparation of 3.60 g(yield: 81%) of Compound 41. Compound 41 was confirmed by LC-MS and¹H-NMR.

C₃₉H₃₂N₂O₂S M+1: 593.3

¹H NMR (500 MHz, CDCl₃) δ=8.09 (d, 2H), 7.93 (t, 1H), 7.87 (d, 1H),7.77-7-42 (m, 16H), 7.32 (d, 2H), 7.27 (d, 1H), 2.51 (s, 3H), 1.71 (s,6H).

Synthesis Example 7: Synthesis of Compound 71

Synthesis of Intermediate 71-1

3,6-dibromo-2-methylpyridine was reacted with 4-bromothiophenol under abasic condition to obtain Intermediate 71-1. Intermediate 71-1 wasconfirmed by LC-MS.

C₁₂H₉Br₂NS, M+1: 357.9

Synthesis of Intermediate 71-2

Intermediate 71-1 was oxidized by using mCPBA to obtain Intermediate71-2. Intermediate 71-2 was confirmed by LC-MS.

C₁₂H₉Br₂NO₂S, M+1: 389.7

Synthesis of Compound 71

1.7 g of Intermediate 71-2, 2.0 g of 9,9-dimethyl-9,10-dihydroacridine,0.058 g of palladium (II) acetate, 0.14 g of triphenylphosphine, and1.24 g of NaOtBu were dissolved in toluene, and the mixture was refluxedfor 3 hours. The obtained reaction solution was cooled to ambienttemperature, and an organic layer was extracted therefrom by using EA,and washed with water. Then, the collected organic layer was dried byusing magnesium sulfate, and the residue obtained by evaporating asolvent therefrom was separation-purified by silica gel columnchromatography, thereby completing the preparation of 1.4 g (yield: 49%)of Compound 71. Compound 71 was confirmed by LC-MS and ¹H-NMR.

C₄₂H₃₇N₃O₂S, M+1: 648.2

¹H NMR (500 MHz, CDCl₃) δ=7.88-7.74 (m, 3H), 7.53 (m, 2H), 7.25 (d, 1H),7.20-7.13 (m, 12H), 6.95 (t, 4H), 2.51 (s, 3H), 1.71 (s, 12H).

Synthesis Example 8: Synthesis of Compound 59

Synthesis of Compound 59

3.3 g of Intermediate 1-2, 3.8 g of (9-phenyl-9H-acarbazole-3-yl)boronic acid, 0.5 g of Pd(PPh₃)₄, and 3.8 g of potassiumcarbonate were loaded into a round-bottom flask, and then, 45 mL oftoluene, 15 mL of ethanol, and 15 mL of distilled water were addedthereto, and the resultant mixture was refluxed overnight. The obtainedreaction solution was cooled to ambient temperature, and an organiclayer was extracted therefrom by using EA, and washed with water. Then,the collected organic layer was dried by using magnesium sulfate, andthe residue obtained by evaporating a solvent therefrom wasseparation-purified by silica gel column chromatography, therebycompleting the preparation of 4.4 g (yield: 87%) of Compound 59.Compound 59 was confirmed by LC-MS and ¹H-NMR.

C₂₉H₂₀N₂O₂S, M+1: 461.2

¹H NMR (500 MHz, CDCl₃) δ=9.1 (s, 1H), 8.31-8.03 (m, 7H), 7.93-7.87 (m,2H), 7.75 (t, 2H), 7.62-7.51 (m, 7H), 7.24 (t, 1H).

Synthesis Example 9: Synthesis of Compound 60

Synthesis of Intermediate 60-1

2,6-dibromipyridine was reacted with thiophenol under a basic conditionto obtain Intermediate 60-1. Intermediate 60-1 was confirmed by LC-MS.

C₁₁H₈BrNS, M+1: 265.9

Synthesis of Intermediate 60-2

Intermediate 60-1 was oxidized by using mCPBA to obtain Intermediate60-2.

Intermediate 60-2 was confirmed by LC-MS.

C₁₁H₈BrNO₂S, M+1 297.9

Synthesis of Compound 60

4.6 g of Intermediate 60-2, 5.3 g of 3-(9H-a carbazole-9-yl)boronicacid, 0.71 g of Pd(PPh₃)₄, and 5.3 g of potassium carbonate were loadedinto a round-bottom flask, and then, 60 mL of toluene, 20 mL of ethanol,and 20 mL of distilled water were added thereto, and the resultantmixture was refluxed overnight. The obtained reaction solution wascooled to ambient temperature, and an organic layer was extractedtherefrom by using EA, and washed with water. Then, the collectedorganic layer was dried by using magnesium sulfate, and the residueobtained by evaporating a solvent therefrom was separation-purified bysilica gel column chromatography, thereby completing the preparation of6.2 g (yield: 88%) of Compound 60. Compound 60 was confirmed by LC-MSand ¹H-NMR.

C₂₉H₂₀N₂O₂S, M+1: 461.1

¹H NMR (500 MHz, CDCl₃) δ=8.57 (s, 1H), 8.19-8.07 (m, 5H), 7.93 (t, 1H),7.75 (t, 2H), 7.68 (t, 1H), 7.61-7.55 (m, 5H), 7.50 (t, 2H), 7.21 (t,2H), 7.16 (d, 1H).

Synthesis Example 10: Synthesis of Compound 61

Synthesis of Compound 61

2.2 g of Intermediate 60-2, 3.6 g of Compound A (CAS No.: 1365090-67-0),0.34 g of Pd(PPh₃)₄, and 2.5 g of potassium carbonate were loaded into around-bottom flask round-bottom flask, and then, 30 mL of toluene, 10 mLof ethanol, and 10 mL of distilled water were added thereto, and theresultant mixture was refluxed overnight. The obtained reaction solutionwas cooled to ambient temperature, and an organic layer was extractedtherefrom by using EA, and washed with water. Then, the collectedorganic layer was dried by using magnesium sulfate, and the residueobtained by evaporating a solvent therefrom was separation-purified bysilica gel column chromatography, thereby completing the preparation of2.2 g (yield: 58%) of Compound 61. Compound 61 was confirmed by LC-MSand ¹H-NMR.

C₃₂H₂₆N₂O₂S, M+1: 503.2

¹H NMR (500 MHz, CDCl₃) δ=8.09 (d, 2H), 7.94-7.87 (m, 2H), 7.75 (t, 2H),7.67 (s, 1H), 7.58 (t, 1H), 7.21-7.12 (m, 7H), 6.99 (t, 2H), 1.71 (s,6H).

Synthesis Example 11: Synthesis of Compound 62

Synthesis of Compound 62

6.7 g of Intermediate 60-2, 12.2 g of Compound A-1 (CAS No.:854952-51-5), 1.0 g of Pd(PPh₃)₄, and 7.7 g of potassium carbonate wereloaded into a round-bottom flask round-bottom flask, and then, 90 mL oftoluene, 30 mL of ethanol, and 30 mL of distilled water were addedthereto, and the resultant mixture was refluxed overnight. The obtainedreaction solution was cooled to ambient temperature, and an organiclayer was extracted therefrom by using EA, and washed with water. Then,the collected organic layer was dried by using magnesium sulfate, andthe residue obtained by evaporating a solvent therefrom wasseparation-purified by silica gel column chromatography, therebycompleting the preparation of 10.4 g (yield: 74%) of Compound 62.Compound 62 was confirmed by LC-MS and ¹H-NMR.

C₄₁H₂₇N₃O₂S, M+1: 626.2

¹H NMR (500 MHz, CDCl₃) δ=8.58 (s, 2H), 8.56 (d, 4H), 8.07 (d, 2H),7.96-7.90 (m, 5H), 7.74 (t, 2H), 7.70-7.59 (m, 2H), 7.55 (t, 1H), 7.35(t, 4H), 7.18-7.12 (m, 5H).

Example 1

As a substrate and an anode, a Corning 15 Ω/cm² (1,200 Å) ITO glasssubstrate was cut to a size of 50 mm×50 mm×0.7 mm, and then, sonicatedby using isopropyl alcohol and pure water, each for 5 minutes, followedby exposure to ultraviolet light for 30 minutes, and then, to ozone. Theresultant glass substrate was provided on a vacuum deposition device.

NPD was vacuum-deposited on the ITO anode on the substrate to form ahole injection layer having a thickness of 300 Å, and TCTA, which is ahole transport compound, was vacuum-deposited thereon to form a holetransport layer having a thickness of 200 Å.

Compound CzSi, which is a compound for forming the hole transport layer,was vacuum-deposited on the hole transport layer having a thickness of100 Å, and then, DPEPO and Compound 1 were co-deposited thereon at aweight ratio of 90:10 to form an emission layer having a thickness of200 Å.

Then, DPEPO was deposited on the emission layer to form an electrontransport layer having a thickness of 200 Å. Then, TPBI wasvacuum-deposited on the electron transport layer to form an electroninjection layer having a thickness of 300 Å. Then, LiF was depositedthereon to a thickness of 10 Å, and then, Al was vacuum-depositedthereon to a thickness of 3,000 Å to form a LiF/Al cathode, therebycompleting the preparation of an organic light-emitting device.

Examples 2 to 7 and Comparative Example 1

Organic light-emitting devices were manufactured in the same manner asin Example 1, except that, in forming the emission layer, compoundsshown in Table 1 were used instead of Compound 1.

Example 8

As a substrate and an anode, a Corning 15 Ω/cm² (1,200 Å) ITO glasssubstrate was cut to a size of 50 mm×50 mm×0.7 mm, and then, sonicatedby using isopropyl alcohol and pure water, each for 5 minutes, followedby exposure to ultraviolet light for 30 minutes, and then, to ozone. Theresultant glass substrate was provided on a vacuum deposition device.

NPD was vacuum-deposited on the ITO anode on the substrate to form ahole injection layer having a thickness of 300 Å, and mCP, which is ahole transport compound, was vacuum-deposited thereon to form a holetransport layer having a thickness of 200 Å.

Compound 1 and Flrpic were co-deposited on the hole transport layer at aweight ratio of 90:10 to form an emission layer having a thickness of250 Å.

Then, TAZ was deposited on the emission layer to form an electrontransport layer having a thickness of 200 Å. Then, LiF was deposited onthe electron transport layer to form an electron injection layer washaving a thickness of 10 Å. Then, Al was vacuum-deposited on theelectron injection layer to form a cathode having a thickness of 100 Å,thereby completing the preparation of an organic light-emitting device.

Example 9 to 14 and a Comparative Example 2

Organic light-emitting devices were manufactured in the same manner asin Example 8, except that, in forming the emission layer, compoundsshown in Table 2 were used instead of Compound 1.

Evaluation Examples 1 and 2

The driving voltage, current density, efficiency, and emission color ofthe organic light-emitting devices of Examples 1 to 7, ComparativeExample 1, and a Comparative Example 2 were measured. Results thereofare shown in Table 1.

TABLE 1 Driving Current maximum Luminescent voltage density Efficiencyquantum Emission TADF material (V) (mA/cm²) (cd/A) efficiency(%) colorExample 1 Compound 1 6.0 2.65 13.9 22 Blue Example 2 Compound 19 5.32.65 14.7 19.5 Blue Example 3 Compound 26 6.2 2.65 15.9 24.5 BlueExample 4 Compound 31 5.7 2.65 14.9 24 Blue Example 5 Compound 32 6.22.65 17.1 22 Blue Example 6 Compound 41 5.6 2.65 18.2 21.8 Blue Example7 Compound 71 5.2 2.65 15.8 19.1 Blue Comparative DPS 6.5 2.65 12.3 17.3Blue Example 1

Referring to Table 1, it may be seen that the organic light-emittingdevices of Examples 1 to 7 had lower driving voltage and higherefficiency than the organic light-emitting device of Comparative Example1.

The driving voltage, current density, efficiency, and emission color ofthe organic light-emitting devices of Examples 8 to 14 and a ComparativeExample 2 were measured. Results thereof are shown in Table 2.

TABLE 2 Driving Current Maximum Luminescent voltage density Efficiencyquantum Emission Host material (V) (mA/cm²) (cd/A) efficiency (%) colorExample 8 1 5.1 2.65 17.4 23.1 Blue Example 9 26 5.2 2.65 15.5 21.4 BlueExample 10 41 4.5 2.65 13.9 22.9 Blue Example 11 59 4.8 2.65 18.1 20.5Blue Example 12 60 5.3 2.65 16.7 22.1 Blue Example 13 61 5.1 2.65 14.221.2 Blue Example 14 62 4.9 2.65 13.3 19.1 Blue Comparative PPC 5.8 2.6511.2 16.1 Blue Example 2

Referring to Table 2, it may be seen that the organic light-emittingdevices of Examples 8 to 14 had lower driving voltage and higherefficiency than the organic light-emitting device of Comparative Example2.

An organic light-emitting device including a heterocyclic compoundaccording to an embodiment may have a low driving voltage, highefficiency, and a long lifespan.

The embodiments may provide an organic light-emitting device having alow driving voltage, high efficiency, and a long lifespan.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. A heterocyclic compound represented by Formula 1:A₁-(A₂)_(n2),  <Formula 1> wherein, in Formula 1, A₁ is a grouprepresented by one of Formulae 2A and 2B,

A₂ is a group represented by Formula 3,

n2 is an integer from 1 to 7, and, when n2 is two or more, groupsrepresented by Formula 3 are identical to or different from each other,in Formulae 2A and 2B, X₁ is N or C(R₁), X₂ is N or C(R₂), X₃ is N orC(R₃), X₄ is N or C(R₄), X₅ is N or C(R₅), X₆ is N or C(R₆), X₇ is N orC(R₇), X₈ is N or C(R₈), X₉ is N or C(R₉), and X₁₀ is N or C(R₁₀), atleast one of X₁ to X₁₀ in Formulae 2A and 2B is N, R₁ to R₁₀ are eachindependently selected from: a binding site to A2 in Formula 1,hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazino group, a hydrazono group, asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —C(═O)(Q₁), and—P(═O)(Q₁)(Q₂), R₁ to R₁₀ are separate or are linked to form asubstituted or unsubstituted condensed ring, L in Formula 3 is selectedfrom a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substitutedor unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted orunsubstituted C₆-C₆₀ arylene group, a substituted or unsubstitutedC₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalentnon-aromatic condensed polycyclic group, and a substituted orunsubstituted divalent non-aromatic condensed heteropolycyclic group,wherein L is not an anthracenylene group or a carbazolylene group, a isan integer from 0 to 3, and, when a is two or more, L(s) are identicalto or different from each other, Ar in Formula 3 is: a group representedby one of Formulae 5-1 to 5-8; or a group represented by one of Formulae6-7 to 6-30, 6-32 to 6-34, 6-36 to 6-46, and 6-48 to 6-55:

wherein, in Formulae 5-1 to 5-8, Y₂₁ is O or S, at least one selectedfrom Y₂₂ and Y₂₃ is CH or N, Z₂₁ to Z₂₄ are each independently selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, acyclohexyl group, a cycloheptyl group, a cyclopentenyl group, acyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group,a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, an indacenyl group, an acenaphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a spiro-benzofluorene-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenylgroup, a pentacenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, a silolyl group, an imidazolyl group, a pyrazolyl group,a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an indolyl group, an isoindolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, an isoquinolinyl group, a phthalazinylgroup, a naphthyridinyl group, a quinoxalinyl group, a benzoquinoxalinylgroup, a quinazolinyl group, a benzoquinazolinyl group, a cinnolinylgroup, a phenanthridinyl group, an acridinyl group, a phenanthrolinylgroup, a phenazinyl group, a benzimidazolyl group, a benzofuranyl group,a benzothiophenyl group, a benzosilolyl group, a benzothiazolyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a carbazolyl group, a dibenzofuranyl group, adibenzothiophenyl group, a dibenzosilolyl group, a benzocarbazolylgroup, a naphthobenzofuranyl group, a naphthobenzothiophenyl group, anaphthobenzosilolyl group, a dibenzocarbazolyl group, a dinaphthofuranylgroup, dinaphthothiophenyl group, a dinaphthosilolyl group, athiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinylgroup, an oxazolopyridinyl group, a thiazolopyridinyl group, abenzonaphthyridinyl group, an azafluorenyl group, anazaspiro-bifluorenyl group, an azacarbazolyl group, an azadibenzofuranylgroup, an azadibenzothiophenyl group, an azadibenzosilolyl group, anindenopyrrolyl group, an indolopyrrolyl group, an indenocarbazolylgroup, an indolocarbazolyl group, benzoacridinyl group, abenzophenanthrenyl group, a dibenzophenanthrenyl group, abenzophenanthridinyl group, a dibenzophenanthridinyl group, anindenophenanthrenyl group, an indolophenanthrenyl group, abenzofuranophenanthrenyl group, a benzothiophenanthrenyl group, abenzosilolphenanthrenyl group, an indenophenanthridinyl group, anindolophenanthridinyl group, benzofuranophenanthridinyl group, abenzothiophenanthridinyl group, a benzosilolphenanthridinyl group, adinaphthopyrrolyl group, a benzoanthracenyl group, and—Si(Q₃₁)(Q₃₂)(Q₃₃), wherein Q₃₁ to Q₃₃ are each independently selectedfrom a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, and anaphthyl group, f2 is an integer from 0 to 2, f3 is an integer from 0 to3, f4 is an integer from 0 to 4, f5 is an integer from 0 to 5, andwherein, in Formulae 6-7 to 6-30, 6-32 to 6-34, 6-36 to 6-46, and 6-48to 6-55, Y₃₁ is O, S, C(Z₃₅)(Z₃₆), N(Z₃₇), or Si(Z₃₈)(Z₃₉), Z₃₁ to Z₃₆,Z₃₈ and Z₃₉ are each independently selected from deuterium, —F, —Cl,—Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, aC₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, acycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenylgroup, a biphenyl group, a terphenyl group, a pentalenyl group, anindenyl group, a naphthyl group, an azulenyl group, an indacenyl group,an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, aspiro-benzofluorene-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a perylenyl group, a pentacenyl group,a pyrrolyl group, a thiophenyl group, a furanyl group, a silolyl group,an imidazolyl group, a pyrazolyl group, a thiazolyl group, anisothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anindolyl group, an isoindolyl group, an indazolyl group, a purinyl group,a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, anisoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a benzoquinoxalinyl group, a quinazolinyl group, abenzoquinazolinyl group, a cinnolinyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, abenzosilolyl group, a benzothiazolyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, a carbazolylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, adibenzosilolyl group, a benzocarbazolyl group, a naphthobenzofuranylgroup, a naphthobenzothiophenyl group, a naphthobenzosilolyl group, adibenzocarbazolyl group, a dinaphthothiophenyl group, a dinaphthosilolylgroup, a thiadiazolyl group, an imidazopyridinyl group, animidazopyrimidinyl group, an oxazolopyridinyl group, a thiazolopyridinylgroup, a benzonaphthyridinyl group, an azafluorenyl group, anazaspiro-bifluorenyl group, an azacarbazolyl group, an azadibenzofuranylgroup, an azadibenzothiophenyl group, an azadibenzosilolyl group, anindenopyrrolyl group, an indolopyrrolyl group, an indenocarbazolylgroup, an indolocarbazolyl group, benzoacridinyl group, abenzophenanthrenyl group, a dibenzophenanthrenyl group, abenzophenanthridinyl group, a dibenzophenanthridinyl group, anindenophenanthrenyl group, an indolophenanthrenyl group, abenzofuranophenanthrenyl group, a benzothiophenanthrenyl group, abenzosilolphenanthrenyl group, an indenophenanthridinyl group, anindolophenanthridinyl group, benzofuranophenanthridinyl group, abenzothiophenanthridinyl group, a benzosilolphenanthridinyl group, adinaphthopyrrolyl group, a benzoanthracenyl group, and—Si(Q₃₁)(Q₃₂)(Q₃₃), wherein Q₃₁ to Q₃₃ are each independently selectedfrom a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, and anaphthyl group, Z₃₇ is selected from deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptylgroup, a cyclopentenyl group, a cyclohexenyl group, a biphenyl group, aterphenyl group, a pentalenyl group, an indenyl group, a naphthyl group,an azulenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-bifluorenyl group, a spiro-benzofluorene-fluorenyl group,a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenylgroup, a pentacenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, a silolyl group, an imidazolyl group, a pyrazolyl group,a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an indolyl group, an isoindolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, an isoquinolinyl group, a phthalazinylgroup, a naphthyridinyl group, a quinoxalinyl group, a benzoquinoxalinylgroup, a quinazolinyl group, a benzoquinazolinyl group, a cinnolinylgroup, a phenanthridinyl group, an acridinyl group, a phenanthrolinylgroup, a phenazinyl group, a benzimidazolyl group, a benzofuranyl group,a benzothiophenyl group, a benzosilolyl group, a benzothiazolyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzosilolyl group, a benzocarbazolyl group, anaphthobenzofuranyl group, a naphthobenzothiophenyl group, anaphthobenzosilolyl group, a dibenzocarbazolyl group,dinaphthothiophenyl group, a dinaphthosilolyl group, a thiadiazolylgroup, an imidazopyridinyl group, an imidazopyrimidinyl group, anoxazolopyridinyl group, a thiazolopyridinyl group, a benzonaphthyridinylgroup, an azafluorenyl group, an azaspiro-bifluorenyl group, anazacarbazolyl group, an azadibenzofuranyl group, an azadibenzothiophenylgroup, an azadibenzosilolyl group, an indenopyrrolyl group, anindolopyrrolyl group, an indenocarbazolyl group, an indolocarbazolylgroup, benzoacridinyl group, a benzophenanthrenyl group, adibenzophenanthrenyl group, a benzophenanthridinyl group, adibenzophenanthridinyl group, an indenophenanthrenyl group, anindolophenanthrenyl group, a benzofuranophenanthrenyl group, abenzothiophenanthrenyl group, a benzosilolphenanthrenyl group, anindenophenanthridinyl group, an indolophenanthridinyl group,benzofuranophenanthridinyl group, a benzothiophenanthridinyl group, abenzosilolphenanthridinyl group, a dinaphthopyrrolyl group, abenzoanthracenyl group, and —Si(Q₃₁)(Q₃₂)(Q₃₃), wherein Q₃₁ to Q₃₃ areeach independently selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxygroup, a phenyl group, and a naphthyl group, e2 is an integer from 0 to2, e3 is an integer from 0 to 3, e4 is an integer from 0 to 4, e5 is aninteger from 0 to 5, e6 is an integer from 0 to 6, e9 is an integer of 0to 9, b is an integer from 1 to 4, and, when b is two or more, Ar(s) areidentical to or different from each other, * indicates a binding site toa neighboring atom, at least one substituent of the substituted C₃-C₁₀cycloalkylene group, substituted C₁-C₁₀ heterocycloalkylene group,substituted C₃-C₁₀ cycloalkenylene group, substituted C₁-C₁₀heterocycloalkenylene group, substituted C₆-C₆₀ arylene group,substituted C₁-C₆₀ heteroarylene group, substituted divalentnon-aromatic condensed polycyclic group, substituted divalentnon-aromatic condensed heteropolycyclic group, substituted C₁-C₆₀ alkylgroup, substituted C₂-C₆₀ alkenyl group, substituted C₂-C₆₀ alkynylgroup, substituted C₁-C₆₀ alkoxy group, substituted C₃-C₁₀ cycloalkylgroup, substituted C₁-C₁₀ heterocycloalkyl group, substituted C₃-C₁₀cycloalkenyl group, substituted C₁-C₁₀ heterocycloalkenyl group,substituted C₆-C₆₀ aryl group, substituted C₆-C₆₀ aryloxy group,substituted C₆-C₆₀ arylthio group, substituted C₁-C₆₀ heteroaryl group,substituted monovalent non-aromatic condensed polycyclic group, andsubstituted monovalent non-aromatic condensed heteropolycyclic group isselected from: deuterium (-D), —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂),—B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂); a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, and a monovalentnon-aromatic condensed heteropolycyclic group; a C₃-C₁₀ cycloalkylgroup, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, aC₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxygroup, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amidino group, a hydrazino group, a hydrazonogroup, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂),—B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and —P(═O)(Q₂₁)(Q₂₂); and—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), wherein Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ toQ₂₃ and Q₃₁ to Q₃₃ are each independently selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkylgroup, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, aC₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromaticcondensed polycyclic group, a monovalent non-aromatic condensedheteropolycyclic group, a biphenyl group, and a terphenyl group.
 2. Theheterocyclic compound as claimed in claim 1, wherein: in Formula 2A, X₁is N, X₂ is C(R₂), X₃ is C(R₃), X₄ is C(R₄), X₅ is C(R₅), X₆ is C(R₆),X₇ is C(R₇), X₈ is C(R₈), X₉ is C(R₉), and X₁₀ is C(R₁₀), and at leastone selected from R₂ to R₁₀ is a binding site to A2 in Formula 1; and inFormula 2B, X₁ is N, X₂ is C(R₂), X₃ is C(R₃), X₄ is C(R₄), X₆ is C(R₆),X₇ is C(R₇), X₈ is C(R₈), and X₉ is C(R₉), and at least one selectedfrom R₂ to R₄ and R₆ to R₉ is a binding site to A2 in Formula
 1. 3. Theheterocyclic compound as claimed in claim 1, wherein: in Formula 2A, X₂is N, X₁ is C(R₁), X₃ is C(R₃), X₄ is C(R₄), X₅ is C(R₅), X₆ is C(R₆),X₇ is C(R₇), X₈ is C(R₈), X₉ is C(R₉), and X₁₀ is C(R₉), and at leastone selected from R₁ and R₃ to R₁₀ is a binding site to A2 in Formula 1;and in Formula 2B, X₂ is N, X₁ is C(R₁), X₃ is C(R₃), X₄ is C(R₄), X₆ isC(R₆), X₇ is C(R₇), X₈ is C(R₈), X₉ is C(R₉), and at least one selectedfrom R₁, R₃, R₄, and R₆ to R₉ is a binding site to A2 in Formula
 1. 4.The heterocyclic compound as claimed in claim 1, wherein: in Formula 2A,X₃ is N, X₁ is C(R₁), X₂ is C(R₂), X₄ is C(R₄), X₅ is C(R₅), X₆ isC(R₆), X₇ is C(R₇), X₈ is C(R₈), X₉ is C(R₉), and X₁₀ is C(R₁₀), and atleast one selected from R₁, R₂, and R₄ to R₁₀ is a binding site to A2 inFormula 1; and in Formula 2B, X₃ is N, X₁ is C(R₁), X₂ is C(R₂), X₄ isC(R₄), X₆ is C(R₆), X₇ is C(R₇), X₈ is C(R₈), and X₉ is C(R₉), and atleast one selected from R₁, R₂, R₄, and R₆ to R₉ is a binding site to A2in Formula
 1. 5. The heterocyclic compound as claimed in claim 1,wherein in Formula 2A, X₁ and X₃ are each N, X₂ is C(R₂), X₄ is C(R₄),X₅ is C(R₅), X₆ is C(R₆), X₇ is C(R₇), X₈ is C(R₈), X₉ is C(R₉), and X₁₀is C(R₁₀), and at least one selected from R₂, R₄ and R₅ to R₁₀ is abinding site to A2 in Formula 1; and in Formula 2B, X₁ and X₃ is N, X₂is C(R₂), X₄ is C(R₄), X₆ is C(R₆), X₇ is C(R₇), X₈ is C(R₈), and X₉ isC(R₉), and at least one from R₂, R₄ and R₆ to R₉ is a binding site to A2in Formula
 1. 6. The heterocyclic compound as claimed in claim 1,wherein in Formula 2A, X₁ and X₆ is N, X₂ is C(R₂), X₃ is C(R₃), X₄ isC(R₄), X₅ is C(R₅), X₇ is C(R₇), X₈ is C(R₈), X₉ is C(R₉), and X₁₀ isC(R₁₀), and at least one selected from R₂ to R₅ and R₇ to R₁₀ is abinding site to A2 in Formula 1, and in Formula 2B, X₁ and X₆ is N, X₂is C(R₂), X₃ is C(R₃), X₄ is C(R₄), X₇ is C(R₇), X₈ is C(R₈), and X₉ isC(R₉), and at least one selected from R₂ to R₄ and R₇ to R₉ is a bindingsite to A2 in Formula
 1. 7. The heterocyclic compound as claimed inclaim 1, wherein: A₁ is a group represented by Formula 2A, in Formula2A, X₁, X₃ and X₅ is N, X₂ is C(R₂), X₄ is C(R₄), X₆ is C(R₆), X₇ isC(R₇), X₈ is C(R₈), X₉ is C(R₉), and X₁₀ is C(R₁₀), and at least oneselected from R₂, R₄ and R₆ to R₁₀ is a binding site to A2 in Formula 1.8. The heterocyclic compound as claimed in claim 1, wherein n2 is aninteger from 1 to
 3. 9. The heterocyclic compound as claimed in claim 1,wherein R₁ to R₁₀ are each independently selected from: a binding siteto A2 in Formula 1; hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxygroup; a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, and a hydrazono group; and —Si(Q₁)(Q₂)(Q₃), wherein R₁ to R₁₀ areseparate or are linked to form a substituted or unsubstituted condensedring, and Q₁ to Q₃ are each independently selected from a C₁-C₁₀ alkylgroup, a C₁-C₁₀ alkoxy group, a phenyl group, and a naphthyl group. 10.The heterocyclic compound as claimed in claim 1, wherein: a in Formula 3is an integer of 1 to 3, and L in Formula 3 is selected from: aphenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anindacenylene group, an acenaphthylene group, a fluorenylene group, aspiro-fluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenalenylene group, a phenanthrenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a naphthacenylene group, a picenylenegroup, a perylenylene group, a pentaphenylene group, a hexacenylenegroup, a pentacenylene group, a rubicenylene group, a coronenylenegroup, an ovalenylene group, a pyrrolylene group, a thiophenylene group,a furanylene group, an imidazolylene group, a pyrazolylene group, athiazolylene group, an isothiazolylene group, an oxazolylene group, anisoxazolylene group, a pyridinylene group, a pyrazinylene group, apyrimidinylene group, a pyridazinylene group, an isoindolylene group, anindolylene group, an indazolylene group, a purinylene group, aquinolinylene group, an isoquinolinylene group, a benzoquinolinylenegroup, a phthalazinylene group, a naphthyridinylene group, aquinoxalinylene group, a quinazolinylene group, a cinnolinylene group, aphenanthridinylene group, an acridinylene group, a dihydroacridinylenegroup, a phenanthrolinylene group, a phenazinylene group, abenzimidazolylene group, a benzofuranylene group, a benzothiophenylenegroup, an isobenzothiazolylene group, a benzoxazolylene group, anisobenzoxazolylene group, a triazolylene group, a tetrazolylene group,an oxadiazolylene group, a triazinylene group, a dibenzofuranylenegroup, a dibenzothiophenylene group, a benzocarbazolylene group, adibenzocarbazolylene group, a thiadiazolylene group, animidazopyridinylene group, and an imidazopyrimidinylene group; and aphenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anindacenylene group, an acenaphthylene group, a fluorenylene group, aspiro-fluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenalenylene group, a phenanthrenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a naphthacenylene group, a picenylenegroup, a perylenylene group, a pentaphenylene group, a hexacenylenegroup, a pentacenylene group, a rubicenylene group, a coronenylenegroup, an ovalenylene group, a pyrrolylene group, a thiophenylene group,a furanylene group, an imidazolylene group, a pyrazolylene group, athiazolylene group, an isothiazolylene group, an oxazolylene group, anisoxazolylene group, a pyridinylene group, a pyrazinylene group, apyrimidinylene group, a pyridazinylene group, an isoindolylene group, anindolylene group, an indazolylene group, a purinylene group, aquinolinylene group, an isoquinolinylene group, a benzoquinolinylenegroup, a phthalazinylene group, a naphthyridinylene group, aquinoxalinylene group, a quinazolinylene group, a cinnolinylene group, aphenanthridinylene group, an acridinylene group, a dihydroacridinylenegroup, a phenanthrolinylene group, a phenazinylene group, abenzimidazolylene group, a benzofuranylene group, a benzothiophenylenegroup, an isobenzothiazolylene group, a benzoxazolylene group, anisobenzoxazolylene group, a triazolylene group, a tetrazolylene group,an oxadiazolylene group, a triazinylene group, a dibenzofuranylenegroup, a dibenzothiophenylene group, a benzocarbazolylene group, adibenzocarbazolylene group, a thiadiazolylene group, animidazopyridinylene group, and an imidazopyrimidinylene group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxylic acidgroup or a salt thereof, a sulfonic acid group or a salt thereof, aphosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptylgroup, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, apentalenyl group, an indenyl group, a naphthyl group, an azulenyl group,a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and—Si(Q₃₁)(Q₃₂)(Q₃₃), wherein Q₃₁ to Q₃₃ are each independently selectedfrom a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, and anaphthyl group.
 11. The heterocyclic compound as claimed in claim 1,wherein: a is an integer of 1 to 3, and L is a group represented by oneof Formulae 4-1 to 4-22 and 4-25 to 4-27:

wherein, in Formulae 4-17 to 4-22, Y₁ is O, S, C(Z₃)(Z₄), or Si(Z₆)(Z₇),wherein, in Formulae 4-1 to 4-16 and 4-25 to 4-27, Y₁ is O, S,C(Z₃)(Z₄), N(Z₅), or Si(Z₆)(Z₇), Z₁ to Z₄, Z₆ and Z₇ are eachindependently selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cyclohexenyl group, a phenyl group, a pentalenylgroup, an indenyl group, a naphthyl group, an azulenyl group, aheptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and—Si(Q₃₁)(Q₃₂)(Q₃₃), wherein Q₃₁ to Q₃₃ are each independently selectedfrom a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, and anaphthyl group, d2 is an integer from 0 to 2, d3 is an integer from 0 to3, d4 is an integer from 0 to 4, d5 is an integer from 0 to 5 d6 is aninteger from 0 to 6, d8 is an integer from 0 to 8, and * and *′ are eacha binding site to a neighboring atom.
 12. The heterocyclic compound asclaimed in claim 11, wherein: L is a group represented by one ofFormulae 4-1, 4-2, and 4-27, and Z₁ and Z₂ in Formulae 4-1, 4-2, and4-27 are each independently be selected from deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxylic acidgroup or a salt thereof, a sulfonic acid group or a salt thereof, aphosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptylgroup, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, apentalenyl group, an indenyl group, a naphthyl group, an azulenyl group,a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and—Si(Q₃₁)(Q₃₂)(Q₃₃), wherein Q₃₁ to Q₃₃ are each independently selectedfrom a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, and anaphthyl group.
 13. The heterocyclic compound as claimed in claim 1,wherein a is 0 or
 1. 14. The heterocyclic compound as claimed in claim1, Ar is a group represented by one of Formulae 5-1 to 5-8, Formula 6-13to 6-16, 6-37 to 6-39, 6-48, and 6-50 to 6-55.
 15. The heterocycliccompound as claimed in claim 1, wherein b is an integer from 1 to
 3. 16.A heterocyclic compound, wherein the heterocyclic compound is one ofCompounds 1 to 102:


17. An organic light-emitting device comprising: a first electrode; asecond electrode facing the first electrode; and an organic layerbetween the first electrode and the second electrode, the organic layercomprising an emission layer, wherein the organic layer includes theheterocyclic compound as claimed in claim
 1. 18. The organiclight-emitting device as claimed in claim 17, wherein: the emissionlayer includes a host and a dopant, and the host or the dopant includesthe heterocyclic compound.
 19. An organic light-emitting devicecomprising: a first electrode; a second electrode facing the firstelectrode; and an organic layer between the first electrode and thesecond electrode, the organic layer comprising an emission layer,wherein the organic layer includes the heterocyclic compound as claimedin claim
 16. 20. The organic light-emitting device as claimed in claim19, wherein: the emission layer includes a host and a dopant, and thehost or the dopant includes the heterocyclic compound.